(234 days)
Not Found
No
The summary describes a standard RT-PCR test and automated instrument system. There is no mention of AI or ML in the intended use, device description, or performance studies. The analysis focuses on traditional analytical and clinical performance metrics.
No
The device is an in vitro diagnostic test for detecting SARS-CoV-2 RNA; it is not intended for treating or curing a disease.
Yes
The "Intended Use" section explicitly states that the test is "intended for use as an aid in the diagnosis of COVID-19." Additionally, the "Device Description" section identifies it as an "in vitro diagnostic test."
No
The device is an in vitro diagnostic test that requires specific hardware (GeneXpert Instrument Systems and single-use cartridges) to perform sample preparation, nucleic acid extraction, amplification, and detection. While it includes preloaded software, it is not solely software.
Yes, this device is an IVD (In Vitro Diagnostic).
Here's why:
- Intended Use: The "Intended Use / Indications for Use" section explicitly states that the test is "intended for the qualitative detection of SARS-CoV-2 RNA in nasopharyngeal and anterior nasal swab specimens collected from individuals with signs and symptoms of respiratory tract infection." This describes a test performed on biological samples taken from the human body to provide information for diagnosis.
- Device Description: The "Device Description" section clearly states that the Xpert Xpress CoV-2 plus test is a "rapid, automated in vitro diagnostic test for the qualitative detection of viral RNA from SARS-CoV-2". The term "in vitro diagnostic" is used directly.
- Nature of the Test: The test is a real-time RT-PCR test performed on biological specimens (nasopharyngeal and anterior nasal swabs) to detect the presence of SARS-CoV-2 RNA. This is a classic example of an in vitro diagnostic test.
- Clinical Performance Evaluation: The document describes a clinical performance evaluation using collected specimens and comparing the results to a "U.S. FDA-cleared molecular respiratory panel". This type of evaluation is standard for IVD devices.
All these points confirm that the Xpert Xpress CoV-2 plus test is an In Vitro Diagnostic device.
N/A
Intended Use / Indications for Use
The Xpert Xpress CoV-2 plus test, performed on the GeneXpert Infinity Systems, is a rapid real-time RT-PCR test intended for the qualitative detection of SARS-CoV-2 RNA in nasopharyngeal and anterior nasal swab specimens collected from individuals with signs and symptoms of respiratory tract infection.
The Xpert Xpress CoV-2 plus test is intended for use as an aid in the diagnosis of COVID-19 if used in conjunction with other clinical, epidemiologic, and laboratory findings. Positive results are indicative of the presence of SARS-CoV-2 RNA. Positive results do not rule out bacterial infection or co-infection with other pathogens.
Negative results do not preclude SARS-CoV-2 infection. The results of this test should not be used as the sole basis for diagnosis and patient management decisions.
Product codes
QQX, OOI
Device Description
The Xpert Xpress CoV-2 plus test is a rapid, automated in vitro diagnostic test for the qualitative detection of viral RNA from SARS-CoV-2 in nasopharyngeal swab (NPS) and anterior nasal swab (NS) specimens obtained from individuals with signs and symptoms of respiratory tract infection.
The Xpert Xpress CoV-2 plus test is performed on the Cepheid GeneXpert® Instrument Systems (GeneXpert Dx, GeneXpert Infinity-48s and GeneXpert Infinity-80 systems), which consist of an instrument, computer and preloaded software for running tests and viewing the results. The GeneXpert Instrument Systems automate and integrate sample preparation, nucleic acid extraction and amplification, and detection of the target sequences in simple or complex samples using real-time reverse transcription (RT)-PCR and PCR assays. Depending on the instrument, the GeneXpert Instrument Systems can have from 1 and up to 80 randomly accessible modules, each capable of performing separate sample preparation and real-time RT-PCR and PCR tests. Each module contains a syringe drive for dispensing fluids (i.e., the syringe drive activates the plunger that works in concert with the rotary valve in the cartridge to move fluids between chambers), an ultrasonic horn for lysing cells or spores, and a proprietary I-CORE® thermocycler for performing real-time RT-PCR and PCR as well as detection. The systems require the use of single-use disposable cartridges that hold the RT-PCR reagents and host sample purification, nucleic acid amplification, and detection of the target sequences. Because the cartridges are selfcontained, cross-contamination between cartridges during the testing process is minimized.
The Xpert Xpress CoV-2 plus test includes reagents for the detection of viral RNA from SARS-CoV-2 in NPS and NS specimens. The primers and probes in the Xpert Xpress CoV-2 plus test are designed to amplify and detect sequences in the genes that encode the following SARS-CoV-2 proteins: nucleocapsid (N2), envelope (E), and RNA-dependent RNA polymerase (RdRP). A Sample Processing Control (SPC) and a Probe Check Control (PCC) are also included in the cartridge utilized by the GeneXpert instrument. The SPC is present to control for adequate processing of the sample and to monitor for the presence of potential inhibitor(s) in the RT-PCR reaction. The SPC also ensures that the RT-PCR reaction conditions (temperature and time) are appropriate for the amplification reaction and that the RT-PCR reagents are functional. The PCC verifies reagent rehydration. PCR tube filling, and confirms that all reaction components are present in the cartridge including monitoring for probe integrity and dve stability.
The Xpert Xpress CoV-2 plus test is designed for use with NPS or NS specimen collected with nylon flocked swabs and placed into a viral transport medium (VTM), Universal Transport Medium (UTM) or eNAT®. Examples of the ancillary specimen collection kits that are compatible for use with the Xpert Xpress CoV-2 plus test include:
- Nasopharyngeal Sample Collection Kit for Viruses
- Copan UTM® 3C057N (Flexible Minitip Flocked Swab with UTM® Medium O w/o Beads)
- Becton Dickinson Universal Viral Transport Kit P/N 220531 (Flexible Minitip O Flocked Swab with UVT Medium)
- Copan eNAT® Molecular Collection and Preservation Medium P/N 6U074S01 O (Flexible Minitip Flocked Swab with eNAT® Medium)
- Nasal Sample Collection Kit for Viruses
- Copan UTM® 3C064N (Regular Flocked Swab with UTM® Medium w/o O Beads)
- Copan eNAT® Molecular Collection and Preservation Medium P/N o 6U073S01 (Regular Flocked Swab with eNAT® Medium)
- Alternatively, swabs and transport media can be obtained separately:
- Nylon flocked swab (Copan P/N 502CS01, 503CS01) O
- Viral transport medium, 3 mL (Copan P/N 3C047N, BD Universal o Transport Medium, Remel M4RT, Remel M5) or equivalent
These sample collection kits for viruses allow NPS and NS specimens from patients to be collected, preserved and transported to laboratory prior to analysis with the Xpert Xpress CoV-2 plus test.
Mentions image processing
Not Found
Mentions AI, DNN, or ML
Not Found
Input Imaging Modality
Not Found
Anatomical Site
nasopharyngeal and anterior nasal swab specimens
Indicated Patient Age Range
Not Found
Intended User / Care Setting
Not Found
Description of the training set, sample size, data source, and annotation protocol
Not Found
Description of the test set, sample size, data source, and annotation protocol
Description of the test set: The clinical performance of the Xpert Xpress CoV-2 plus test was evaluated using prospectively collected fresh (98.6%) and frozen (1.4%) clinical nasopharyngeal swab (NPS) and anterior nasal swab (NS) specimens in viral transport medium or universal transport medium.
Sample size: A total of 4047 specimens (2029 NPS and 2018 NS) were evaluated. After exclusions, a total of 3750 (1879 NPS and 1871 NS) specimens that yielded valid results by both Xpert Xpress CoV-2 plus and the U.S. FDA-cleared molecular respiratory panel were included in the clinical performance evaluation.
Data source: Specimens were collected from individuals with signs and symptoms of respiratory infection.
Annotation protocol: Specimens were tested using Xpert Xpress CoV-2 plus side by side with a U.S. FDA-cleared molecular respiratory panel that includes SARS-CoV-2, in a randomized and blinded fashion.
Summary of Performance Studies (study type, sample size, AUC, MRMC, standalone performance, key results)
Analytical Performance
- Analytical Sensitivity/Limit of Detection (LoD) - Clinical NPS Matrix
- Study Type: LoD estimation and verification by testing limiting dilutions of NATtrol inactivated SARS-CoV-2 virus.
- Sample Size: Replicates of 20 per lot for two clinical NPS matrices (UTM/VTM and eNAT), using two reagent lots.
- Key Results: The claimed LoD is 403 copies/mL.
- Analytical Sensitivity/Limit of Detection (LoD) – Clinical NS-UTM/VTM Matrix
- Study Type: LoD estimation and verification by testing limiting dilutions of NATtrol inactivated SARS-CoV-2 virus.
- Sample Size: Replicates of 20 per lot for clinical NS-UTM/VTM matrix, using two reagent lots.
- Key Results: The claimed LoD is 462 copies/mL.
- Analytical Sensitivity (Limit of Detection) - WHO First International Standard SARS-CoV-2 RNA in clinical NS-UTM/VTM Matrix
- Study Type: LoD estimation by testing limiting dilutions of WHO First International Standard for SARS-CoV-2 RNA.
- Sample Size: Not explicitly stated for replicates, but aimed to achieve >95% positive results.
- Key Results: The verified LoD for the First WHO International Standard for SARS-CoV-2 RNA tested in NS-UTM/VTM matrix was 1000 IU/mL.
- Analytical Inclusivity (Reactivity)
- SARS-CoV-2 in silico Analyses
- Study Type: In silico analysis of assay amplicons and probe oligonucleotides against SARS-CoV-2 sequences.
- Sample Size: 11,650,640 SARS-CoV-2 sequences from GISAID gene database (for amplicons), and top 20 most frequent matches (10,310,839 to 10,428,014 sequences for probes).
- Key Results: Predicted inclusivity of 100% for E and RdRP amplicons, and 99.95% for N2 amplicon. Predicted inclusivity of 100% for E and N2 probes, and 99.6% for RdRP probe. Analysis predicted detection of all currently circulating variants/lineages.
- SARS-CoV-2 Wet-Testing
- Study Type: Bench testing against multiple strains of SARS-CoV-2.
- Sample Size: 61 strains (23 intact SARS-CoV-2 viral particles and 38 SARS-CoV-2 in vitro RNA transcripts). Three replicates per strain.
- Key Results: All SARS-CoV-2 strains tested positive in all three replicates.
- SARS-CoV-2 in silico Analyses
- Analytical Exclusivity (Specificity)
- In Silico Analyses
- Study Type: In silico mapping of primers and probes to microorganism sequences from NCBI.
- Key Results: No potential unintended cross-reactivity expected, except for SARS-coronavirus (E gene target).
- Wet-Testing
- Study Type: Bench-testing a panel of microorganisms.
- Sample Size: 62 microorganisms (4 human coronaviruses, 1 MERS-coronavirus, 1 SARS-coronavirus, 20 other respiratory viruses, 30 respiratory bacteria, 2 yeast strains, 3 fungal strains, 1 human nasal wash fluid).
- Key Results: No cross-reactivity observed, except for SARS-coronavirus, Urbani, which yielded a SARS-CoV-2 POSITIVE result due to conserved E gene target.
- In Silico Analyses
- Microbial Interference
- Study Type: Assessment of inhibitory effects of commensal microorganisms.
- Sample Size: 18 commensal microorganisms (15 viral, 3 bacterial). 8 positive replicates for each combination.
- Key Results: All 8 of 8 positive replicate samples were correctly identified as SARS-CoV-2 POSITIVE. No interference reported.
- Potentially Interfering Substances
- Study Type: Evaluation of substances with direct testing.
- Sample Size: 23 potentially interfering substances. 8 negative and 8 positive samples tested per substance.
- Key Results: Interference observed for fluticasone propionate (at 5 µg/mL) and mucin type I-S (at 2.5 mg/mL), causing INVALID results in some replicates. Interference was resolved by reducing concentrations by half. All other substances showed no interference.
- Carryover Contamination
- Study Type: Assessment of specimen and amplicon carryover.
- Sample Size: 40 high positive samples and 42 negative samples.
- Key Results: All 40 positive samples correctly reported as SARS-CoV-2 POSITIVE and all 42 negative samples correctly reported as SARS-CoV-2 NEGATIVE. No carry-over contamination observed.
- Reproducibility
- Study Type: Multi-site reproducibility study.
- Sample Size: 3-member panel (negative, low positive, moderate positive). 144 observations per panel member (3 Sites x 2 Operators x 3 Lots x 2 Days/Lot x 2 Runs x 2 Replicates).
- Key Results:
- Negative: 99.3% total agreement (95% CI: 96.1% - 99.9%).
- SARS-CoV-2 Low Pos: 100% total agreement (95% CI: 97.4% - 100%).
- SARS-CoV-2 Mod Pos: 100% total agreement (95% CI: 97.4% - 100%).
- Low CV values for Ct values indicate good precision.
- Single-Site Precision
- Study Type: Single-site precision study.
- Sample Size: 3-member panel (negative, low positive, moderate positive). 80 observations per panel member (1 Site x 1 Operator x 1 Lot x 20 Days x 2 Runs x 2 Replicates).
- Key Results: 100% agreement for all panel members (95% CI: 95.4% - 100.0%).
Clinical Performance
- Study Type: Multi-site, observational and method comparison study.
- Sample Size: 3750 specimens (1879 NPS and 1871 NS) that yielded valid results by both Xpert Xpress CoV-2 plus and the U.S. FDA-cleared molecular respiratory panel.
- Key Results:
- Overall Positive Percent Agreement (PPA): 98.1% (95% CI: 96.7% - 98.9%) for SARS-CoV-2.
- Overall Negative Percent Agreement (NPA): 98.3% (95% CI: 97.7% - 98.7%) for SARS-CoV-2.
- PPA for NPS: 97.0% (95% CI: 94.4% - 98.4%).
- NPA for NPS: 98.2% (95% CI: 97.4% - 98.8%).
- PPA for NS: 99.3% (95% CI: 97.5% - 99.8%).
- NPA for NS: 98.3% (95% CI: 97.5% - 98.8%).
Key Metrics (Sensitivity, Specificity, PPV, NPV, etc.)
Positive Percent Agreement (PPA): 98.1% (95% CI: 96.7% - 98.9%)
Negative Percent Agreement (NPA): 98.3% (95% CI: 97.7% - 98.7%)
Predicate Device(s)
BioFire COVID-19 Test 2 (K211079)
Reference Device(s)
Not Found
Predetermined Change Control Plan (PCCP) - All Relevant Information
Not Found
§ 866.3981 Device to detect and identify nucleic acid targets in respiratory specimens from microbial agents that cause the SARS-CoV-2 respiratory infection and other microbial agents when in a multi-target test.
(a)
Identification. A device to detect and identify nucleic acid targets in respiratory specimens from microbial agents that cause the SARS-CoV-2 respiratory infection and other microbial agents when in a multi-target test is an in vitro diagnostic device intended for the detection and identification of SARS-CoV-2 and other microbial agents when in a multi-target test in human clinical respiratory specimens from patients suspected of respiratory infection who are at risk for exposure or who may have been exposed to these agents. The device is intended to aid in the diagnosis of respiratory infection in conjunction with other clinical, epidemiologic, and laboratory data or other risk factors.(b)
Classification. Class II (special controls). The special controls for this device are:(1) The intended use in the labeling required under § 809.10 of this chapter must include a description of the following: Analytes and targets the device detects and identifies, the specimen types tested, the results provided to the user, the clinical indications for which the test is to be used, the specific intended population(s), the intended use locations including testing location(s) where the device is to be used (if applicable), and other conditions of use as appropriate.
(2) Any sample collection device used must be FDA-cleared, -approved, or -classified as 510(k) exempt (standalone or as part of a test system) for the collection of specimen types claimed by this device; alternatively, the sample collection device must be cleared in a premarket submission as a part of this device.
(3) The labeling required under § 809.10(b) of this chapter must include:
(i) A detailed device description, including reagents, instruments, ancillary materials, all control elements, and a detailed explanation of the methodology, including all pre-analytical methods for processing of specimens;
(ii) Detailed descriptions of the performance characteristics of the device for each specimen type claimed in the intended use based on analytical studies including the following, as applicable: Limit of Detection, inclusivity, cross-reactivity, interfering substances, competitive inhibition, carryover/cross contamination, specimen stability, precision, reproducibility, and clinical studies;
(iii) Detailed descriptions of the test procedure(s), the interpretation of test results for clinical specimens, and acceptance criteria for any quality control testing;
(iv) A warning statement that viral culture should not be attempted in cases of positive results for SARS-CoV-2 and/or any similar microbial agents unless a facility with an appropriate level of laboratory biosafety (
e.g., BSL 3 and BSL 3+, etc.) is available to receive and culture specimens; and(v) A prominent statement that device performance has not been established for specimens collected from individuals not identified in the intended use population (
e.g., when applicable, that device performance has not been established in individuals without signs or symptoms of respiratory infection).(vi) Limiting statements that indicate that:
(A) A negative test result does not preclude the possibility of infection;
(B) The test results should be interpreted in conjunction with other clinical and laboratory data available to the clinician;
(C) There is a risk of incorrect results due to the presence of nucleic acid sequence variants in the targeted pathogens;
(D) That positive and negative predictive values are highly dependent on prevalence;
(E) Accurate results are dependent on adequate specimen collection, transport, storage, and processing. Failure to observe proper procedures in any one of these steps can lead to incorrect results; and
(F) When applicable (
e.g., recommended by the Centers for Disease Control and Prevention, by current well-accepted clinical guidelines, or by published peer-reviewed literature), that the clinical performance may be affected by testing a specific clinical subpopulation or for a specific claimed specimen type.(4) Design verification and validation must include:
(i) Detailed documentation, including performance results, from a clinical study that includes prospective (sequential) samples for each claimed specimen type and, as appropriate, additional characterized clinical samples. The clinical study must be performed on a study population consistent with the intended use population and compare the device performance to results obtained using a comparator that FDA has determined is appropriate. Detailed documentation must include the clinical study protocol (including a predefined statistical analysis plan), study report, testing results, and results of all statistical analyses.
(ii) Risk analysis and documentation demonstrating how risk control measures are implemented to address device system hazards, such as Failure Modes Effects Analysis and/or Hazard Analysis. This documentation must include a detailed description of a protocol (including all procedures and methods) for the continuous monitoring, identification, and handling of genetic mutations and/or novel respiratory pathogen isolates or strains (
e.g., regular review of published literature and periodic in silico analysis of target sequences to detect possible mismatches). All results of this protocol, including any findings, must be documented and must include any additional data analysis that is requested by FDA in response to any performance concerns identified under this section or identified by FDA during routine evaluation. Additionally, if requested by FDA, these evaluations must be submitted to FDA for FDA review within 48 hours of the request. Results that are reasonably interpreted to support the conclusion that novel respiratory pathogen strains or isolates impact the stated expected performance of the device must be sent to FDA immediately.(iii) A detailed description of the identity, phylogenetic relationship, and other recognized characterization of the respiratory pathogen(s) that the device is designed to detect. In addition, detailed documentation describing how to interpret the device results and other measures that might be needed for a laboratory diagnosis of respiratory infection.
(iv) A detailed device description, including device components, ancillary reagents required but not provided, and a detailed explanation of the methodology, including molecular target(s) for each analyte, design of target detection reagents, rationale for target selection, limiting factors of the device (
e.g., saturation level of hybridization and maximum amplification and detection cycle number, etc.), internal and external controls, and computational path from collected raw data to reported result (e.g., how collected raw signals are converted into a reported signal and result), as applicable.(v) A detailed description of device software, including software applications and hardware-based devices that incorporate software. The detailed description must include documentation of verification, validation, and hazard analysis and risk assessment activities, including an assessment of the impact of threats and vulnerabilities on device functionality and end users/patients as part of cybersecurity review.
(vi) For devices intended for the detection and identification of microbial agents for which an FDA recommended reference panel is available, design verification and validation must include the performance results of an analytical study testing the FDA recommended reference panel of characterized samples. Detailed documentation must be kept of that study and its results, including the study protocol, study report for the proposed intended use, testing results, and results of all statistical analyses.
(vii) For devices with an intended use that includes detection of Influenza A and Influenza B viruses and/or detection and differentiation between the Influenza A virus subtypes in human clinical specimens, the design verification and validation must include a detailed description of the identity, phylogenetic relationship, or other recognized characterization of the Influenza A and B viruses that the device is designed to detect, a description of how the device results might be used in a diagnostic algorithm and other measures that might be needed for a laboratory identification of Influenza A or B virus and of specific Influenza A virus subtypes, and a description of the clinical and epidemiological parameters that are relevant to a patient case diagnosis of Influenza A or B and of specific Influenza A virus subtypes. An evaluation of the device compared to a currently appropriate and FDA accepted comparator method. Detailed documentation must be kept of that study and its results, including the study protocol, study report for the proposed intended use, testing results, and results of all statistical analyses.
(5) When applicable, performance results of the analytical study testing the FDA recommended reference panel described in paragraph (b)(4)(vi) of this section must be included in the device's labeling under § 809.10(b) of this chapter.
(6) For devices with an intended use that includes detection of Influenza A and Influenza B viruses and/or detection and differentiation between the Influenza A virus subtypes in human clinical specimens in addition to detection of SARS-CoV-2 and similar microbial agents, the required labeling under § 809.10(b) of this chapter must include the following:
(i) Where applicable, a limiting statement that performance characteristics for Influenza A were established when Influenza A/H3 and A/H1-2009 (or other pertinent Influenza A subtypes) were the predominant Influenza A viruses in circulation.
(ii) Where applicable, a warning statement that reads if infection with a novel Influenza A virus is suspected based on current clinical and epidemiological screening criteria recommended by public health authorities, specimens should be collected with appropriate infection control precautions for novel virulent influenza viruses and sent to State or local health departments for testing. Viral culture should not be attempted in these cases unless a BSL 3+ facility is available to receive and culture specimens.
(iii) Where the device results interpretation involves combining the outputs of several targets to get the final results, such as a device that both detects Influenza A and differentiates all known Influenza A subtypes that are currently circulating, the device's labeling must include a clear interpretation instruction for all valid and invalid output combinations, and recommendations for any required followup actions or retesting in the case of an unusual or unexpected device result.
(iv) A limiting statement that if a specimen yields a positive result for Influenza A, but produces negative test results for all specific influenza A subtypes intended to be differentiated (
i.e., H1-2009 and H3), this result requires notification of appropriate local, State, or Federal public health authorities to determine necessary measures for verification and to further determine whether the specimen represents a novel strain of Influenza A.(7) If one of the actions listed at section 564(b)(1)(A) through (D) of the Federal Food, Drug, and Cosmetic Act occurs with respect to an influenza viral strain, or if the Secretary of Health and Human Services determines, under section 319(a) of the Public Health Service Act, that a disease or disorder presents a public health emergency, or that a public health emergency otherwise exists, with respect to an influenza viral strain:
(i) Within 30 days from the date that FDA notifies manufacturers that characterized viral samples are available for test evaluation, the manufacturer must have testing performed on the device with those influenza viral samples in accordance with a standardized protocol considered and determined by FDA to be acceptable and appropriate.
(ii) Within 60 days from the date that FDA notifies manufacturers that characterized influenza viral samples are available for test evaluation and continuing until 3 years from that date, the results of the influenza emergency analytical reactivity testing, including the detailed information for the virus tested as described in the certificate of authentication, must be included as part of the device's labeling in a tabular format, either by:
(A) Placing the results directly in the device's labeling required under § 809.10(b) of this chapter that accompanies the device in a separate section of the labeling where analytical reactivity testing data can be found, but separate from the annual analytical reactivity testing results; or
(B) In a section of the device's label or in other labeling that accompanies the device, prominently providing a hyperlink to the manufacturer's public website where the analytical reactivity testing data can be found. The manufacturer's website, as well as the primary part of the manufacturer's website that discusses the device, must provide a prominently placed hyperlink to the website containing this information and must allow unrestricted viewing access.
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October 13, 2023
Image /page/0/Picture/1 description: The image shows the logo of the U.S. Food and Drug Administration (FDA). The logo consists of two parts: the Department of Health & Human Services logo on the left and the FDA logo on the right. The FDA logo includes the letters "FDA" in a blue square, followed by the words "U.S. FOOD & DRUG" in blue, with the word "ADMINISTRATION" underneath.
Cepheid Jennifer Motto Principal Regulatory Affairs Specialist 904 Caribbean Drive Sunnyvale, California 94089
Re: K230440
Trade/Device Name: Xpert Xpress CoV-2 plus Regulation Number: 21 CFR 866.3981 Regulation Name: Device To Detect And Identify Nucleic Acid Targets In Respiratory Specimens From Microbial Agents That Cause The SARS-Cov-2 Respiratory Infection And Other Microbial Agents When In A Multi-Target Test Regulatory Class: Class II Product Code: QQX, OOI Dated: September 1, 2023 Received: September 12, 2023
Dear Jennifer Motto:
We have reviewed your section 510(k) premarket notification of intent to market the device referenced above and have determined the device is substantially equivalent (for the indications for use stated in the enclosure) to legally marketed predicate devices marketed in interstate commerce prior to May 28, 1976, the enactment date of the Medical Device Amendments, or to devices that have been reclassified in accordance with the provisions of the Federal Food, Drug, and Cosmetic Act (the Act) that do not require approval of a premarket approval application (PMA). You may, therefore, market the device, subject to the general controls provisions of the Act. Although this letter refers to your product as a device, please be aware that some cleared products may instead be combination products. The 510(k) Premarket Notification Database available at https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfpmn/pmn.cfm identifies combination product submissions. The general controls provisions of the Act include requirements for annual registration, listing of devices, good manufacturing practice, labeling, and prohibitions against misbranding and adulteration. Please note: CDRH does not evaluate information related to contract liability warranties. We remind you, however, that device labeling must be truthful and not misleading.
If your device is classified (see above) into either class II (Special Controls) or class III (PMA), it may be subject to additional controls. Existing major regulations affecting your device can be found in the Code of Federal Regulations, Title 21, Parts 800 to 898. In addition, FDA may publish further announcements concerning your device in the Federal Register.
Additional information about changes that may require a new premarket notification are provided in the FDA guidance documents entitled "Deciding When to Submit a 510(k) for a Change to an Existing Device"
1
(https://www.fda.gov/media/99812/download) and "Deciding When to Submit a 510(k) for a Software Change to an Existing Device" (https://www.fda.gov/media/99785/download).
Your device is also subject to, among other requirements, the Quality System (QS) regulation (21 CFR Part 820), which includes, but is not limited to, 21 CFR 820.30. Design controls; 21 CFR 820.90. Nonconforming product; and 21 CFR 820.100, Corrective and preventive action. Please note that regardless of whether a change requires premarket review. the OS regulation requires device manufacturers to review and approve changes to device design and production (21 CFR 820.30 and 21 CFR 820.70) and document changes and approvals in the device master record (21 CFR 820.181).
Please be advised that FDA's issuance of a substantial equivalence determination does not mean that FDA has made a determination that your device complies with other requirements of the Act or any Federal statutes and regulations administered by other Federal agencies. You must comply with all the Act's requirements, including, but not limited to: registration and listing (21 CFR Part 807); labeling (21 CFR Part 801 and Part 809); medical device reporting of medical device-related adverse events) (21 CFR Part 803) for devices or postmarketing safety reporting (21 CFR Part 4, Subpart B) for combination products (see https://www.fda.gov/combination-products/guidance-regulatory-information/postmarketing-safetyreporting-combination-products); good manufacturing practice requirements as set forth in the quality systems (QS) regulation (21 CFR Part 820) for devices or current good manufacturing practices (21 CFR Part 4, Subpart A) for combination products; and, if applicable, the electronic product radiation control provisions (Sections 531-542 of the Act); 21 CFR Parts 1000-1050.
Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21 CFR 807.97). For questions regarding the reporting of adverse events under the MDR regulation (21 CFR Part 803), please go to https://www.fda.gov/medical-device-safety/medical-device-reportingmdr-how-report-medical-device-problems.
For comprehensive regulatory information about mediation-emitting products, including information about labeling regulations, please see Device Advice (https://www.fda.gov/medicaldevices/device-advice-comprehensive-regulatory-assistance) and CDRH Learn (https://www.fda.gov/training-and-continuing-education/cdrh-learn). Additionally, you may contact the Division of Industry and Consumer Education (DICE) to ask a question about a specific regulatory topic. See the DICE website (https://www.fda.gov/medical-device-advice-comprehensive-regulatoryassistance/contact-us-division-industry-and-consumer-education-dice) for more information or contact DICE by email (DICE@fda.hhs.gov) or phone (1-800-638-2041 or 301-796-7100).
Sincerely. Himani Bisht -S
Himani Bisht, Ph.D. Assistant Director Viral Respiratory and HPV Branch Division of Microbiology Devices OHT7: Office of In Vitro Diagnostics Office of Product Evaluation and Quality
2
Enclosure
3
Indications for Use
510(k) Number (if known) K230440
Device Name Xpert Xpress CoV-2 plus
Indications for Use (Describe)
The Xpert Xpress CoV-2 plus test, performed on the GeneXpert Infinity Systems, is a rapid real-time RT-PCR test intended for the qualitative detection of SARS-CoV-2 RNA in nasopharyngeal and anterior nasal swab specimens collected from individuals with signs and symptoms of respiratory tract infection.
The Xpert Xpress CoV-2 plus test is intended for use as an aid in the diagnosis of COVID-19 if used in conjunction with other clinical, epidemiologic, and laboratory findings. Positive results are indicative of the presence of SARS-CoV-2 RNA. Positive results do not rule out bacterial infection or co-infection with other pathogens.
Negative results do not preclude SARS-CoV-2 infection. The results of this test should not be used as for diagnosis and patient management decisions.
Type of Use (Select one or both, as applicable)
☑ Prescription Use (Part 21 CFR 801 Subpart D) |
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☐ Over-The-Counter Use (21 CFR 801 Subpart C) |
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Image /page/4/Picture/0 description: The image contains the logo for Cepheid, a molecular diagnostics company. The logo features a stylized blue wing-like graphic above the company name. Below the company name, the text "Xpert® Xpress CoV-2 plus" is displayed, indicating a product related to COVID-19 testing.
5. 510(k) Summary
As required by 21 CFR Section 807.92(c).
| Submitted by: | Cepheid
904 Caribbean Drive
Sunnyvale, CA 90489
Phone number: (408) 541-4191 |
|----------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| Contact: | Jennifer Motto, M.S., RAC |
| Date of Preparation: | February 17, 2023 |
| Device: | |
| Trade name:
Common name:
Type of Test: | Xpert® Xpress CoV-2 plus
Xpert Xpress CoV-2 plus
Qualitative real-time reverse transcription polymerase chain
reaction (RT-PCR) and detection test |
| Regulation number:
Classification name: | 21 CFR 866.3981
Multi-target respiratory specimen nucleic acid test including
SARS-CoV-2 and other microbial agents,
Respiratory Specimen Nucleic Acid SARS-CoV-2 Test, |
| Primary product
code: | QQX |
| Secondary product
code | OOI |
| Classification
Advisory Panel | Microbiology (83) |
| Prescription Use | Yes |
| Predicate Device
Assay: | BioFire COVID-19 Test 2 (K211079) |
5
5.1. Device Description
The Xpert Xpress CoV-2 plus test is a rapid, automated in vitro diagnostic test for the qualitative detection of viral RNA from SARS-CoV-2 in nasopharyngeal swab (NPS) and anterior nasal swab (NS) specimens obtained from individuals with signs and symptoms of respiratory tract infection.
The Xpert Xpress CoV-2 plus test is performed on the Cepheid GeneXpert® Instrument Systems (GeneXpert Dx, GeneXpert Infinity-48s and GeneXpert Infinity-80 systems), which consist of an instrument, computer and preloaded software for running tests and viewing the results. The GeneXpert Instrument Systems automate and integrate sample preparation, nucleic acid extraction and amplification, and detection of the target sequences in simple or complex samples using real-time reverse transcription (RT)-polymerase chain reaction (PCR) and PCR assays. Depending on the instrument, the GeneXpert Instrument Systems can have from 1 and up to 80 randomly accessible modules, each capable of performing separate sample preparation and real-time RT-PCR and PCR tests. Each module contains a syringe drive for dispensing fluids (i.e., the syringe drive activates the plunger that works in concert with the rotary valve in the cartridge to move fluids between chambers), an ultrasonic horn for lysing cells or spores, and a proprietary I-CORE® thermocycler for performing real-time RT-PCR and PCR as well as detection. The systems require the use of single-use disposable cartridges that hold the RT-PCR reagents and host sample purification, nucleic acid amplification, and detection of the target sequences. Because the cartridges are selfcontained, cross-contamination between cartridges during the testing process is minimized.
The Xpert Xpress CoV-2 plus test includes reagents for the detection of viral RNA from SARS-CoV-2 in NPS and NS specimens. The primers and probes in the Xpert Xpress CoV-2 plus test are designed to amplify and detect sequences in the genes that encode the following SARS-CoV-2 proteins: nucleocapsid (N2), envelope (E), and RNA-dependent RNA polymerase (RdRP). A Sample Processing Control (SPC) and a Probe Check Control (PCC) are also included in the cartridge utilized by the GeneXpert instrument. The SPC is present to control for adequate processing of the sample and to monitor for the presence of potential inhibitor(s) in the RT-PCR reaction. The SPC also ensures that the RT-PCR reaction conditions (temperature and time) are appropriate for the amplification reaction and that the RT-PCR reagents are functional. The PCC verifies reagent rehydration. PCR tube filling, and confirms that all reaction components are present in the cartridge including monitoring for probe integrity and dve stability.
The Xpert Xpress CoV-2 plus test is designed for use with NPS or NS specimen collected with nylon flocked swabs and placed into a viral transport medium (VTM), Universal Transport Medium (UTM) or eNAT®. Examples of the ancillary specimen collection kits that are compatible for use with the Xpert Xpress CoV-2 plus test include:
6
. Nasopharyngeal Sample Collection Kit for Viruses
- Copan UTM® 3C057N (Flexible Minitip Flocked Swab with UTM® Medium O w/o Beads)
- Becton Dickinson Universal Viral Transport Kit P/N 220531 (Flexible Minitip O Flocked Swab with UVT Medium)
- Copan eNAT® Molecular Collection and Preservation Medium P/N 6U074S01 O (Flexible Minitip Flocked Swab with eNAT® Medium)
● Nasal Sample Collection Kit for Viruses
- Copan UTM® 3C064N (Regular Flocked Swab with UTM® Medium w/o O Beads)
- Copan eNAT® Molecular Collection and Preservation Medium P/N o 6U073S01 (Regular Flocked Swab with eNAT® Medium)
- Alternatively, swabs and transport media can be obtained separately:
- Nylon flocked swab (Copan P/N 502CS01, 503CS01) O
- Viral transport medium, 3 mL (Copan P/N 3C047N, BD Universal o Transport Medium, Remel M4RT, Remel M5) or equivalent
These sample collection kits for viruses allow NPS and NS specimens from patients to be collected, preserved and transported to laboratory prior to analysis with the Xpert Xpress CoV-2 plus test.
5.2. Device Intended Use
The Xpert Xpress CoV-2 plus test, performed on the GeneXpert Dx and GeneXpert Infinity Systems, is a rapid real-time RT-PCR test intended for the qualitative detection of SARS-CoV-2 RNA in nasopharyngeal and anterior nasal swab specimens collected from individuals with signs and symptoms of respiratory tract infection.
The Xpert Xpress CoV-2 plus test is intended for use as an aid in the diagnosis of COVID-19 if used in conjunction with other clinical, epidemiologic, and laboratory findings. Positive results are indicative of the presence of SARS-CoV-2 RNA. Positive results do not rule out bacterial infection or co-infection with other pathogens.
Negative results do not preclude SARS-CoV-2 infection. The results of this test should not be used as the sole basis for diagnosis and patient management decisions.
5.3. Substantial Equivalence
Table 5-1 shows the similarities and differences between Xpert Xpress CoV-2 plus and the predicate device, BioFire COVID-19 Test 2 [K211079].
7
Table 5-1. Comparison of Similarities and Differences Between Xpert Xpress CoV-2 plus and | ||
---|---|---|
the Predicate Device |
| Attribute | New Device
Cepheid
Xpert® Xpress CoV-2 plus | Predicate Device – K211079
BioFire Defense, LLC
BioFire COVID-19 Test 2 |
|--------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| Regulation | Same | 21 CFR 866.3981
Devices to detect and identify nucleic acid targets in respiratory samples from microbial agents that cause the SARS-CoV-2 respiratory infection and other microbial agents when in a multi-analyte test |
| Product Code | Same | QQX
Respiratory Specimen Nucleic Acid SARS-CoV-2 Test |
| Device Class | Same | II (Special Controls) |
| Technology/
Detection | Real-time reverse transcription polymerase chain reaction (RT-qPCR) | Nested multiplex RT-PCR followed by high resolution melting analysis to confirm identity of amplified product |
| Intended Use | The Xpert Xpress CoV-2 plus test, performed on the GeneXpert Dx and GeneXpert Infinity Systems, is a rapid real-time RT-PCR test intended for the qualitative detection of SARS-CoV-2 RNA in nasopharyngeal and anterior nasal swab specimens collected from individuals with signs and symptoms of respiratory tract infection.
The Xpert Xpress CoV-2 plus test is intended for use as an aid in the diagnosis of COVID-19 if used in conjunction with other clinical, epidemiologic, and laboratory findings. Positive results are indicative of the presence of SARS-CoV-2 RNA. Positive results do not rule out bacterial infection or co-infection with other pathogens.
Negative results do not preclude SARS-CoV-2 infection. The results of this test should not be used as the sole basis for diagnosis and patient management decisions. | The BioFire COVID-19 Test 2 is a qualitative nested multiplexed RT-PCR in vitro diagnostic test intended for use with the BioFire FilmArray 2.0 and BioFire FilmArray Torch Systems. The BioFire COVID-19 Test 2 detects nucleic acids from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in nasopharyngeal swabs (NPS) from symptomatic individuals suspected of COVID-19 by their healthcare provider.
Results are for the identification of SARS-CoV-2 RNA. The SARS-CoV-2 RNA is generally detectable in NPS specimens during the acute phase of infection. Positive results are indicative of the presence of SARS-CoV-2 RNA; clinical correlation with patient history and other diagnostic information is necessary to determine patient infection status. Positive results do not rule out co-infection with other pathogens.
Results are meant to be used in conjunction with other clinical, epidemiologic, and laboratory data, in accordance with the guidelines provided by the relevant public health authorities. The BioFire COVID-19 Test 2 is intended for use by trained medical and laboratory professionals in a |
| | New Device | Predicate Device - K211079 |
| Attribute | Cepheid
Xpert® Xpress CoV-2 plus | BioFire Defense, LLC
BioFire COVID-19 Test 2
laboratory setting or under the supervision
of a trained laboratory professional. |
| Assay Targets | SARS-CoV-2
(E, N2, RdRP) | SARS-CoV-2
(Multiple Targets) |
| Specimen Type | • Nasopharyngeal swab (NPS)
• Anterior nasal swab (NS) | Nasopharyngeal swab (NPS) |
| Transport
Media | • Universal Transport Medium (UTM) /
Viral Transport Medium (VTM)
• eNAT | • Transport Medium
• Saline |
| Test Format | Same | Single Use |
| Automation | Same | Automated Nucleic Acid Extraction,
Detection and Results Interpretation |
| Assay Results | Same | Qualitative |
| Internal
Control | • Sample Processing Control (SPC)
• Probe Check Control (PCC) | • Sample Processing Control
• PCR and Melt Analysis Control |
| Instrument
Systems | Cepheid GeneXpert® Instrument Systems | BioFire® FilmArray® 2.0 or
BioFire® FilmArray® Torch Systems |
| Time to Result | ~30 minutes | ~ 45 minutes |
8
Image /page/8/Picture/0 description: The image features the Cepheid logo, which includes a stylized blue wing-like design above the word "Cepheid" in a serif font. Below the logo, the text "Xpert® Xpress CoV-2 plus" is displayed, with "Xpert" followed by a registered trademark symbol. The text is in a smaller, sans-serif font, indicating a product or service related to COVID-19 testing.
Traditional 510(k) Submission
The following performance data (analytical and clinical) were provided in support of the substantial equivalence determination.
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5.4. Performance Studies
5.4.1. Analytical Performance
Analytical Sensitivity/Limit of Detection (LoD) - Clinical NPS Matrix
The analytical sensitivity of the Xpert Xpress CoV-2 plus test was first estimated by testing limiting dilutions of a NATtrol inactivated SARS-CoV-2 virus in pooled negative clinical NPS-UTM/VTM matrix, using two reagent lots and following the guidance in Clinical and Laboratory Standards Institute (CLSI) document EP17-A2. LoD was estimated by considering each target gene (E, N2, and RdRP) in addition to the overall positivity rate for the Xpert Xpress CoV-2 plus test. The estimated LoD value as determined by Probit regression analysis was based on the weakest target gene (N2) and verified using two lots of Xpert Xpress CoV-2 plus reagents in replicates of 20 per lot for two clinical NPS matrices (UTM/VTM and eNAT). The concentration levels with observed hit rates greater than or equal to 95% in the LoD determination study were 403, 200 and 70 copies/mL for the N2 target, RdRP target and E target, respectively. The claimed LoD is 403 copies/mL (Tables 5-2 and 5-3).
Table 5-2. Xpert Xpress CoV-2 plus Limit of Detection -- Verification of NATtrol SARS-CoV-2 LoD in NPS-UTM/VTM Matrix
| Virus Strain | Reagent Lot | LoD
(copies/mL) | Positive
Results out
of # Valid
Replicates | %
Positive | Mean
E Ct | Mean
N2 Ct | Mean
RdRP Ct |
|------------------------|---------------|--------------------|-----------------------------------------------------|---------------|--------------|---------------|-----------------|
| NATtrol™
SARS-CoV-2 | Reagent Lot 1 | 403 | 20/20 | 100% | 34.3 | 38.3 | 36.6 |
| | Reagent Lot 2 | 403 | 20/20 | 100% | 34.1 | 37.7 | 36.5 |
Table 5-3. Xpert Xpress CoV-2 plus Limit of Detection - Verification of NATtrol SARS-CoV-2 LoD in NPS-eNAT Matrix
| Virus Strain | Reagent Lot | LoD
(copies/mL) | Positives
out of #
Valid
Replicates | %
Positive | Mean
E Ct | Mean
N2 Ct | Mean
RdRP Ct |
|--------------|---------------|--------------------|----------------------------------------------|---------------|--------------|---------------|-----------------|
| NATtrol™ | Reagent Lot 1 | 403 | 20/20ª | 100% | 33.4 | 36.8 | 35.5 |
| SARS-CoV-2 | Reagent Lot 2 | 403 | 20/20 | 100% | 33.5 | 36.8 | 35.5 |
a. One of 20 replicates tested reported INVALID. The run was successfully repeated to obtain 20 valid replicates.
Analytical Sensitivity/Limit of Detection (LoD) – Clinical NS-UTM/VTM Matrix
The analytical sensitivity of the Xpert Xpress CoV-2 plus test was first estimated by testing limiting dilutions of a NATtrol inactivated SARS-CoV-2 virus in pooled negative clinical NS-UTM/VTM matrix, using two reagent lots and following the guidance in Clinical and Laboratory Standards Institute (CLSI) document EP17-A2. LoD was estimated by considering each target gene (E, N2, and RdRP) in addition to the overall positivity rate for the Xpert Xpress CoV-2 plus test. The LoD point estimates and 95% upper and lower confidence intervals (CI) for individual SARS-CoV-2 targets (E, N2 and RdRP) in clinical
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Image /page/10/Picture/0 description: The image contains the logo for Cepheid, a molecular diagnostics company. The logo features a stylized blue wing-like shape above the company name. Below the company name is the text "Xpert® Xpress CoV-2 plus", which refers to one of Cepheid's diagnostic tests.
NS-UTM/VTM matrix were determined using Probit regression analysis and the point estimated LoD values were 97, 462 and 157 copies/mL for the E target, N2 target and RdRP target, respectively. The estimated LoD value of the weakest target gene (N2) was verified using two lots of Xpert Xpress CoV-2 plus reagents in replicates of 20 per lot for clinical NS-UTM/VTM matrix. The claimed LoD is 462 copies/mL (Table 5-4).
Table 5-4. Xpert Xpress CoV-2 plus Limit of Detection - Verification of NATtrol SARS-CoV-2 LoD in NS-UTM/VTM Matrix
| Virus Strain | Reagent Lot | LoD
(copies/mL) | Positive
Results out
of # of
Valid
Replicates | %
Positive | Mean
E Ct | Mean
N2 Ct | Mean
RdRP Ct |
|------------------------|---------------|--------------------|-----------------------------------------------------------|---------------|--------------|---------------|-----------------|
| NATtrol™
SARS-CoV-2 | Reagent Lot 1 | 462 | 20/20 | 100% | 34.4 | 38.9 | 36.8 |
| | Reagent Lot 2 | 462 | 20/20 | 100% | 34.1 | 37.6 | 36.1 |
Analytical Sensitivity (Limit of Detection) - WHO First International Standard SARS-CoV-2 RNA in clinical NS-UTM/VTM Matrix
The analytical sensitivity of the Xpert Xpress CoV-2 plus test was estimated by testing limiting dilutions of WHO First International Standard for SARS-CoV-2 RNA in pooled negative clinical NS-UTM/VTM matrix, using one reagent lot. The study was performed in a random and blinded fashion.
The lowest concentration level of the First WHO International Standard for SARS-CoV-2 RNA that generated >95% positive results (19/20 positive results) for the weakest target gene (N2) by the Xpert Xpress CoV-2 plus test was used to confirm be the analytical sensitivity or Limit of Detection (LoD). The verified LoD for the First WHO International Standard for SARS-CoV-2 RNA tested in NS-UTM/VTM matrix with the Xpert Xpress CoV-2 plus test was 1000 IU/mL. The positivity rates for the overall SARS-CoV-2 results and the analyte targets, including the mean Ct values for E, N2 and RdRP at the verified LoD are presented in Table 5-5.
Table 5-5. LoD Concentration, Positivity Rate and Mean Ct Values for SARS-CoV-2 for the First WHO International Standard for SARS-CoV-2 RNA in Clinical NS-UTM/VTM Matrix
| Virus | LoD
Concentration | SARS-CoV-2
Positive
Results / Test
Replicates | E Target | | N2 Target | | RdRP Target | |
|---------------------------------------------------------------------|----------------------|--------------------------------------------------------|----------|------|-----------|------|-------------|------|
| 1st WHO
International
Standard for
SARS-CoV-2
RNA Virus | 1000 IU/mL | 20/20 | 20/20 | 34.3 | 19/20 | 39.5 | 20/20 | 36.5 |
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Analytical Inclusivity (Reactivity)
SARS-CoV-2 in silico Analyses
The inclusivity of Xpert Xpress CoV-2 plus primers was evaluated on June 30th, 2022 using in silico analysis of the assay amplicons in relation to 11,650,640 SARS-CoV-2 sequences available in the GISAID gene database for three targets, E, N2 and RdRP. The 11,650,640 SARS-CoV-2 sequences were separated into the lineages of interest based on the Pango Lineage assigned to each genome by GISAID, and those with ambiguous nucleotides were removed. Thus, the following inclusivity analyses focuses on the combined, non-ambiguous sequences from the variants of interest and variants of concern as of June 30th, 2022. These constituted 10.469.612 sequences for the E target. 10.587.381 sequences for the N2 target and 10,333,656 sequences for the RdRP target. Table 5-6 summarizes the effective predicted inclusivity for E, N2 and RdRP amplicons for the variants of interests and concern.
Table 5-6. Predicted Inclusivity for E, N2 and RdRP Amplicons for SARS-CoV-2 Variants of Interests and Concern
| SARS-CoV-2
Target Amplicon | Exact Match | 1 Mismatch a | 2 or More
Mismatches | Predicted
Inclusivity |
|-------------------------------|-------------------------------------------|-------------------|-------------------------|--------------------------|
| E | 10,420,248 of 10,469,612 total
(99.5%) | 48,562
(0.5%) | 802
(0.01%) | 100% |
| N2 | 10,386,068 of 10,587,381 total
(98.1%) | 196,336
(1.9%) | 4,977
(0.05%) | 99.95% |
| RdRP | 10,247,146 of 10,333,656 total
(99.2%) | 85,373
(0.8%) | 1,137
(0.01%) | 100% |
Single-nucleotide mismatches are predicted to not impact the performance of the test. a.
The in silico inclusivity of the Xpert Xpress CoV-2 plus probe oligonucleotides for E, N2 and RdRP were also assessed against the top 20 most frequent matches in the GISAID EpiCoV sequence database as of June 15th, 2022, which constituted 10,310, 839 for the E target, 10,428,014 for the N2 target and 10,178,602 for the RdRP target. For each of the probe oligonucleotides used in the Xpert Xpress CoV-2 plus test. Table 5-7 summarizes the number sequences as well as the corresponding percentage of sequences from this dataset with exact match, 1 mismatch/insertion, and 2 or more mismatches/insertions in the alignment.
Table 5-7. Predicted Inclusivity for E, N2 and RdRP Probes for SARS-CoV-2 Variants of Interests and Concern
| SARS-CoV-2
Target Probe | Exact Match | 1 Mismatch/Insertion a | 2 or More
Mismatches/
Insertions | Predicted
Inclusivity |
|----------------------------|-------------------------------------------|------------------------------------------|----------------------------------------|--------------------------|
| E | 10,300,688 of 10,310,839 total
(99.9%) | 9,853
(0.1%) | 22
(0.0002%) | 100% |
| N2 | 10,351,581 of 10,428,014 total
(99.3%) | 72,957
(0.7%) | 0
(0%) | 100% |
| RdRP | 0 | 10,140,254 of 10,178602 total
(99.6%) | 37,492
(0.4%) | 99.6% |
Single-nucleotide mismatches/insertions are predicted to not impact the performance of the test. a.
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The in silico inclusivity of the Xpert Xpress CoV-2 plus primer/probe sequences for E, N2 and RdRP was further assessed against SAR-CoV-2 sequences submitted to the GISAID EpiCoV database up to 180 days prior to and including July 31, 2023 for SARS-CoV-2 isolates currently circulating in the United States. There were no instances where a specific primer/probe sequence was observed with greater than 0.5% frequency of mismatch during this 180-day period. The analysis predicted that the Xpert Xpress CoV-2 plus test will detect all currently circulating variants/lineages of SARS-CoV-2.
Moreover, based on the built-in redundancy of the Xpert Xpress CoV-2 plus test's SARS-CoV-2 amplification system (i.e., 3 independent targets, only 1 of 3 must be detected to assign a positive result), it is not anticipated that any of the evaluated sequences would be missed by the Xpert Xpress CoV-2 plus test.
SARS-CoV-2 Wet-Testing
In addition to the in silico analysis of the SARS-CoV-2 primers and probes for inclusivity, the inclusivity of the Xpert Xpress CoV-2 plus test was evaluated by bench testing against multiple strains of SARS-CoV-2 at levels near the analytical LoD (~3x LoD). A total of 61 strains comprised of 23 intact SARS-CoV-2 viral particles (18 inactivated viral cultures and 5 BSL-3 live viral cultures), and 38 SARS-CoV-2 in vitro RNA transcripts representing variant strains were tested in this study with the Xpert Xpress CoV-2 plus test. Three replicates were tested for each strain. All SARS-CoV-2 strains tested positive in all three replicates. Results are shown in Table 5-8.
| Count
No. | SARS-CoV-2 Strain | Tested
Concentration | SARS-CoV-2
Test Results | Number of Positive Results
Obtained out of the Total Number of
Valid Replicates | | | |
|--------------|------------------------------------------------|--------------------------------|----------------------------|---------------------------------------------------------------------------------------|---------------------------------------------------------------------------------|------|------|
| | | | | E | N2 | RdRP | |
| 1 | 2019-nCoV/Italy-INMI1 a | 5 TCID50/mL | POS | 3/3 | 3/3 | 3/3 | |
| 2 | England/204820464/2020 a | 0.5 TCID50/mL | POS e | 3/3 | 3/3 | 3/3 | |
| 3 | Hong Kong/VM20001061/2020 a | 0.25 TCID50/mL | POS | 3/3 | 3/3 | 3/3 | |
| 4 | South Africa/KRISP-K005325/2020 a | 0.25 TCID50/mL | POS | 3/3 | 3/3 | 3/3 | |
| 5 | USA/CA_CDC_5574/2020 a | 0.25 TCID50/mL | POS | 3/3 | 3/3 | 3/3 | |
| 6 | USA/MD-HP01542/2021 a | 1.3e3 genome
equivalents/mL | POS | 3/3 | 3/3 | 3/3 | |
| 7 | USA/GA-EHC-2811C/2021 a | 1.3e3 genome
equivalents/mL | POS | 3/3 | 3/3 | 3/3 | |
| 8 | NY-Wadsworth-103677-01/2020 a | 0.15 TCID50/mL | POS | 3/3 | 3/3 | 3/3 | |
| 9 | NY-Wadsworth-21006055-01/2021 a | 0.04 TCID50/mL | POS | 3/3 | 3/3 | 3/3 | |
| 10 | NY-Wadsworth-21025952-01/2021 a
(Isolate 1) | 0.625 TCID50/mL | POS | 3/3 | 3/3 | 3/3 | |
| 11 | NY-Wadsworth-21018781-01/2021 a
(Isolate 2) | 0.625 TCID50/mL | POS | 3/3 | 3/3 | 3/3 | |
| Count
No. | SARS-CoV-2 Strain | Tested
Concentration | SARS-CoV-2
Test Results | | Number of Positive Results Obtained out of the Total Number of Valid Replicates | | |
| | | | | | E | N2 | RdRP |
| 12 | NY-Wadsworth-21033899-01/2021 a | 1.25 TCID50/mL | POS | | 3/3 | 3/3 | 3/3 |
| 13 | NY-Wadsworth-33126-01/2020 a | 0.15 TCID50/mL | POS | | 3/3 | 3/3 | 3/3 |
| 14 | USA/CA-Stanford-15_S02/2021a | 0.04 TCID50/mL | POS | | 3/3 | 3/3 | 3/3 |
| 15 | USA/PHC658/2021a | 25 TCID50/mL | POS | | 3/3 | 3/3 | 3/3 |
| 16 | Japan/TY7-503/2021a | 0.75 TCID50/mL | POS | | 3/3 | 3/3 | 3/3 |
| 17 | hCoV-19/USA/MD-HP30386/2022 a | 27.5 copies/mL | POS | | 3/3 | 3/3 | 3/3 |
| 18 | hCoV-19/USA/COR-22-063113/2022 a | 19 copies/mL | POS | | 3/3 | 3/3 | 3/3 |
| 19 | Australia/VIC01/2020 b | 1.2e3 copies/mL | POS | | 3/3 | 3/3 | 3/3 |
| 20 | Belgium/ULG/10004/2020b | 1.2e3 copies/mL | POS | | 3/3 | 3/3 | 3/3 |
| 21 | England/205041766/2020b | 1.2e3 copies/mL | POS | | 3/3 | 3/3 | 3/3 |
| 22 | England/MILK-9E05B3/2020b | 1.2e3 copies/mL | POS | | 3/3 | 3/3 | 3/3 |
| 23 | England/SHEF-C05B2/2020b | 1.2e3 copies/mL | POS | | 3/3 | 3/3 | 3/3 |
| 24 | France/HF2393/2020b | 1.2e3 copies/mL | POS | | 3/3 | 3/3 | 3/3 |
| 25 | Hong Kong/HKU-211129-001/2021b | 1.2e3 copies/mL | POS | | 3/3 | 3/3 | 3/3 |
| 26 | Iceland/5/2020b | 1.2e3 copies/mL | POS | | 3/3 | 3/3 | 3/3 |
| 27 | India/CT-ILSGS00361/2021 b | 1.2e3 copies/mL | POS | | 3/3 | 3/3 | 3/3 |
| 28 | India/MH-NCCS-
P1162000182735/2021b | 1.2e3 copies/mL | POS | | 3/3 | 3/3 | 3/3 |
| 29 | India/MH-SEQ-
221_S66_R1_001/2021b | 1.2e3 copies/mL | POS | | 3/3 | 3/3 | 3/3 |
| 30 | Japan/Hu_DP_Kng_19-020/2020b | 1.2e3 copies/mL | POS | | 3/3 | 3/3 | 3/3 |
| 31 | Japan/IC-0564/2021 b | 1.2e3 copies/mL | POS | | 3/3 | 3/3 | 3/3 |
| 32 | Portugal/PT9543/2021b | 1.2e3 copies/mL | POS | | 3/3 | 3/3 | 3/3 |
| 33 | South Africa/KRISP-EC-
K005299/2020b | 1.2e3 copies/mL | POS | | 3/3 | 3/3 | 3/3 |
| 34 | Taiwan/NTU02/2020 b | 1.2e3 copies/mL | POS | | 3/3 | 3/3 | 3/3 |
| 35 | USA/CA9/2020b | 1.2e3 copies/mL | POS | | 3/3 | 3/3 | 3/3 |
| 36 | USA/CA-PC101P/2020 b | 1.2e3 copies/mL | POS | | 3/3 | 3/3 | 3/3 |
| 37 | USA/CA-CZB-12943/2020 b | 1.2e3 copies/mL | POS | | 3/3 | 3/3 | 3/3 |
| 38 | USA/MN2-MDH2/2020b | 1.2e3 copies/mL | POS | | 3/3 | 3/3 | 3/3 |
| 39 | USA/NY-MSHSPSP-PV24650/2020b | 1.2e3 copies/mL | POS | | 3/3 | 3/3 | 3/3 |
| 40 | USA/TX1/2020b | 1.2e3 copies/mL | POS | | 3/3 | 3/3 | 3/3 |
| 41 | USA/WA2/2020 b | 1.2e3 copies/mL | POS | | 3/3 | 3/3 | 3/3 |
| 42 | USA/WA-CDC-
UW21061750277/2021b | 1.2e3 copies/mL | POS | | 3/3 | 3/3 | 3/3 |
| 43 | Wuhan-Hu-1 b | 1.2e3 copies/mL | POS | | 3/3 | 3/3 | 3/3 |
| Count
No. | SARS-CoV-2 Strain | Tested
Concentration | SARS-CoV-2
Test Results | Number of Positive Results
Obtained out of the Total Number of
Valid Replicates | | | |
| | | | | E | N2 | RdRP | |
| 44 | Germany/BavPat1/2020c | 1.2e3 genome
copies/mL | POS | 3/3 | 3/3 | 3/3 | |
| 45 | Singapore/2/2020c | 300 genome
equivalents/mL | POS | 3/3 | 3/3 | 3/3 | |
| 46 | USA/AZ1/2020c | 300 genome
equivalents/mL | POS | 3/3 | 3/3 | 3/3 | |
| 47 | USA/CA1/2020c | 1.2e3 genome
equivalents/mL | POS | 3/3 | 3/3 | 3/3 | |
| 48 | USA/CA2/2020c | 1.2e3 genome
equivalents/mL | POS | 3/3 | 3/3 | 3/3 | |
| 49 | USA/CA3/2020c | 400 genome
equivalents/mL | POS | 3/3 | 3/3 | 3/3 | |
| 50 | USA/CA4/2020c | 1.2e3 genome
equivalents/mL | POS | 3/3 | 3/3 | 3/3 | |
| 51 | USA/IL1/2020c | 150 genome
equivalents/mL | POS | 3/3 | 3/3 | 3/3 | |
| 52 | USA/New York-PV08001/2020c | 1.2e3 genome
copies/mL | POS | 3/3 | 3/3 | 3/3 | |
| 53 | USA/New York-PV08410/2020c | 300 genome
equivalents/mL | POS | 3/3 | 3/3 | 3/3 | |
| 54 | USA/New York-PV08449/2020c | 300 genome
equivalents/mL | POS | 3/3 | 3/3 | 3/3 | |
| 55 | USA/New York-PV09158/2020c | 300 genome
equivalents/mL | POS | 3/3 | 3/3 | 3/3 | |
| 56 | USA/WI1/2020c | 1.2e3 genome
equivalents/mL | POS | 3/3 | 3/3 | 3/3 | |
| 57 | hCoV-19/USA/MD-HP38861/2022 d | 0.29 TCID50/mL | POS | 3/3 | 3/3 | 3/3 | |
| 58 | hCoV-19/USA/MD-HP38960/2022 d | 0.043 TCID50/mL | POS | 3/3 | 3/3 | 3/3 | |
| 59 | hCoV-19/USA/CO-CDPHE-
2102544747/2021 d | 0.028 TCID50/mL | POS | 3/3 | 3/3 | 3/3 | |
| 60 | hCoV-19/USA/MD-HP38288/2022 d | 0.24 TCID50/mL | POS | 3/3 | 3/3 | 3/3 | |
| 61 | hCoV-19/USA/MD-HP40900/2022 d | 0.72 TCID50/mL | POS | 3/3 | 3/3 | 3/3 | |
Table 5-8. Analytical Reactivity (Inclusivity) of the Xpert Xpress CoV-2 plus Test
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Image /page/13/Picture/0 description: The image shows the Cepheid logo and product name. The Cepheid logo is a blue, stylized wing shape. Below the logo is the text "Cepheid." in a serif font. The product name "Xpert® Xpress CoV-2 plus" is written in a smaller, sans-serif font below the company name.
Traditional 510(k) Submission
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Image /page/14/Picture/0 description: The image contains the Cepheid logo and the text "Xpert® Xpress CoV-2 plus". The Cepheid logo is a blue graphic element above the word "Cepheid.". The text "Xpert® Xpress CoV-2 plus" is below the logo.
Traditional 510(k) Submission
Inactivated viral culture fluid (intact viral particles) a.
Synthetic, in vitro RNA transcript, TWIST controls b.
Genomic RNA C.
d.
BSL-3 live viral culture fluid (intact viral particles)
One of 3 replicates reported ERROR. The run was successfully repeated to obtain 3 valid replicates. e.
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Analytical Exclusivity (Specificity)
In Silico Analyses
The analytical specificity/cross-reactivity of the Xpert Xpress CoV-2 plus plan included evaluation of the SARS-CoV-2 test primer and probes with potentially cross-reactive microorganisms by in silico analysis was conducted by mapping the primers and probes of Xpert Xpress CoV-2 plus individually to the microorganism sequences downloaded from the NCBI database. E primers and probes are not specific for SARS-COV-2 and will detect Human and Bat SARS-coronavirus. No potential unintended cross reactivity with other organisms listed in Table 5-9 is expected based on the in silico analysis.
| Microorganisms from the Same Genetic
Family | High Priority Organisms |
---|---|
Human coronavirus 229E | Adenovirus (e.g., C1 Ad. 71) |
Human coronavirus OC43 | Cytomegalovirus |
Human coronavirus HKU1 | Enterovirus (e.g., EV68) |
Human coronavirus NL63 | Epstein-Barr virus |
SARS-coronavirus | Human Metapneumovirus (hMPV) |
MERS-coronavirus | Influenza A & B |
Bat coronavirus | Measles |
Mumps | |
Parainfluenza virus 1-4 | |
Parechovirus | |
Respiratory syncytial virus | |
Rhinovirus | |
Bacillus anthracis (Anthrax) | |
Bordetella pertussis | |
Bordetella parapertussis | |
Chlamydia pneumoniae | |
Chlamydia psittaci | |
Corynebacterium diphtheriae | |
Coxiella burnetii (Q-Fever) | |
Escherichia coli | |
Fusobacterium necrophorum | |
Haemophilus influenzae | |
Lactobacillus sp. | |
Legionella non-pneumophila | |
Legionella pneumophila | |
Leptospira | |
Moraxella catarrhalis | |
Mycobacterium tuberculosis | |
Mycoplasma genitalium | |
Mycoplasma pneumoniae | |
Neisseria elongata | |
Neisseria meningitidis |
Table 5-9. Microorganisms Analyzed in the in silico Analysis for the SARS-CoV-2 Target
16
| Microorganisms from the Same Genetic
Family | High Priority Organisms |
---|---|
Pneumocystis jirovecii (PJP) | |
Pseudomonas aeruginosa | |
Staphylococcus aureus | |
Staphylococcus epidermidis | |
Staphylococcus salivarius | |
Streptococcus pneumoniae | |
Streptococcus pyogenes | |
Aspergillus sp | |
Candida albicans |
Wet-Testing
In addition to the in silico analysis of the SARS-CoV-2 primers and probes for crossreactivity, the analytical specificity of the Xpert Xpress CoV-2 plus test was evaluated by bench-testing a panel of 62 microorganisms comprising (4) human coronaviruses, (1) MERScoronavirus, (1) SARS-coronavirus, (20) other respiratory viruses, (30) respiratory bacteria, (2) yeast strains, (3) fungal strain, and 1 human nasal wash fluid representing a diverse microbial flora in the human respiratory tract.
The intact viruses were tested at concentrations of ≥10° TCID50/mL, ≥10° CEID50/mL, and >105 copies/mL. Bacteria and yeast were tested at ≥10° CFU/mL. The bacteria Chlamydia pneumoniae and Mycoplasma pneumoniae were tested at concentrations of ≥10° IFU/mL and >106 CCU/mL. respectively. The live strains of Coxiella burnetii. Lactobacillus reuteri, and Neisseria meningitides were not available, therefore genomic DNA at ≥ 10° genome equivalent copies/mL was used. The in vitro transcribed (IVT) RNA sample was tested at > 10° genome equivalent/mL for human Coronavirus HKU1, and the genomic RNA sample was tested at > 10° genome equivalent/mL for SARS-coronavirus Urbani.
The microorganisms being evaluated for cross-reactivity were tested in groups or individually and spiked into negative simulated NPS/NS background matrix for testing. If a grouped microorganisms produced a SARS-CoV-2 positive result, then each member of the group was tested separately. If the individual non-target organism yielded a positive result, retesting was performed at lower concentrations until a concentration that no longer produce a false positive result was identified.
The results of the analytical specificity/exclusivity study demonstrate that the primer/probe sets included in the Xpert Xpress CoV-2 plus does not cross-react with the nucleic acids from non-intended respiratory microorganisms and phylogenetically related human coronavirus species. The one exception was the SARS-coronavirus, Urbani which yielded the expected test result of SARS-CoV-2 POSITIVE. We expected cross-reactivity for the E gene target with the SARS-coronavirus Urbani strain which has the highly conserved E gene target shared among coronaviruses in the B lineage Betacoronavirus. Results are shown in Table 5-10.
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Traditional 510(k) Submission
Table 5-10. Analytical Specificity (Exclusivity) of the Xpert Xpress CoV-2 plus Test | ||
---|---|---|
-------------------------------------------------------------------------------------- | -- | -- |
| Respiratory Microorganisms | Test
Group | Tested Concentration | Final
SARS-CoV-2
Result Call- Number of Positive Results
Obtained from Total Number
of Replicates Tested | | | |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|---------------|------------------------------------|------------------------------------------------------------------------------------------------------------------------|----------------------------------------------------------------------------------|------|------|
| | | | E | N2 | RdRP | |
| Human coronavirus, 229E
Human coronavirus, OC43
MERS-coronavirus | G1 | 1.1e5 TCID50/mL | NEG | 0/3 | 0/3 | 0/3 |
| Human coronavirus, NL63 | G2 | 1.1e5 TCID50/mL | NEG | 0/3 | 0/3 | 0/3 |
| Human coronavirus, HKU1a | G3 | 1.1e6 genome cp/mL | NEG | 0/3 | 0/3 | 0/3 |
| SARS-coronavirus, Urbani a | G4 | 1.1e6 genome cp/mL | POS | 3/3 | 0/3 | 0/3 |
| Influenza A H1N1 (pdm2009),
Michigan/272/2017 | | 1.1e5 TCID50/mL | | | | |
| Influenza B (Victoria Lineage),
Hawaii/01/2018 (NA D197N) | G5 | 1.1e5 TCID50/mL | NEG | 0/3 | 0/3 | 0/3 |
| RSV-A, Strain: 4/2015 Isolate #1 | | 1.1e5 TCID50/mL | | | | |
| Adenovirus Type 1 | | 1.1e5 TCID50/mL | | | | |
| Adenovirus Type 7A
Cytomegalovirus
Echovirus | G6 | 1.1e5 TCID50/mL | NEG | 0/3 | 0/3 | 0/3 |
| Enterovirus, D68 strain US/KY/14-18953
Epstein Barr Virus (Human Herpes Virus 4
[Hhv-4]) | | 1.1e5 TCID50/mL
1.1e5 cp/mL | | | | |
| Herpes Simplex Virus (HSV) type 1
Human metapneumovirus
(hMPV-5, type B1) | G7 | 1.1e5 TCID50/mL | NEG | 0/3 | 0/3 | 0/3 |
| Measles
Mumps virus
Human parainfluenza Type 1
Human parainfluenza Type 2 | | 1.1e5 TCID50/mL | | | | |
| Human parainfluenza Type 3
Human parainfluenza Type 4
Rhinovirus, Type 1A b | G8 | 1.1e5 TCID50/mL
4.5e4 TCID50/mL | NEG | 0/3 | 0/3 | 0/3 |
| Acinetobacter baumannii
Burkholderia cepacia
Candida albicans
Candida parapsilosis
Bordetella pertussis
Chlamydia pneumoniae
Citrobacter freundii
Corynebacterium xerosis | G9 | 1.1e6 CFU/mL
1.1e6 IFU/mL | NEG | 0/3 | 0/3 | 0/3 |
| Escherichia coli
Enterococcus faecalis
Hemophilus influenzae
Legionella spp d
Moraxella catarrhalis
Mycobacterium tuberculosis (avirulent)
Mycoplasma pneumoniae
Neisseria mucosa | G10 | 1.1e6 CFU/mL
1.1e6 CCU/mL | NEG | 0/3 | 0/3 | 0/3 |
| Propionibacterium acnes (= Cutibacterium
acnes) Z144 | G11 | 1.1e6 CFU/mL | NEG | 0/3 | 0/3 | 0/3 |
| Pseudomonas aeruginosa, Z139
Staphylococcus aureus
Staphylococcus epidermidis
Staphylococcus haemolyticus | G12 | 1.1e6 CFU/mL | NEG | 0/3 | 0/3 | 0/3 |
| Respiratory Microorganisms | Test
Group | Tested Concentration | Final
SARS-CoV-2
Result Call-
Out | Number of Positive Results
Obtained from Total Number
of Replicates Tested | | |
| | | | | E | N2 | RdRP |
| Streptococcus agalactiae | | 1.1e6 CFU/mL | | | | |
| Streptococcus pneumoniae | | 1.1e6 CFU/mL | | | | |
| Streptococcus pyogenes | | 1.1e6 CFU/mL | | | | |
| Streptococcus salivarius | | 1.1e6 CFU/mL | | | | |
| Streptococcus sanguinis | | 1.1e6 CFU/mL | | | | |
| Pneumocystis jirovecii (PJP) | | 1.1e6 CFU/mL | | | | |
| Lactobacillus reuteri, F275c | G13 | 1.1e6 genome cp/mL | NEG | 0/3 | 0/3 | 0/3 |
| Neisseria meningitides c | G13 | 1.1e6 genome cp/mL | NEG | 0/3 | 0/3 | 0/3 |
| Pooled human nasal wash | G14 | N/A | NEG | 0/3 | 0/3 | 0/3 |
| Influenza C (Taylor/1233/1947) | G15 | 1.1e5 CEID50/mL | NEG | 0/3 | 0/3 | 0/3 |
| Rhinovirus, Type 1Ab | G16 | 1.1e5 TCID50/mL | NEG | 0/3 | 0/3 | 0/3 |
| Aspergillus flavus | G17 | 1.35e7 CFU/mL | NEG | 0/3 | 0/3 | 0/3 |
| Aspergillus fumigatus | G18 | 3.67e6 CFU/mL | NEG | 0/3 | 0/3 | 0/3 |
| Coxiella burnetii c | G19 | 2.5e6 genome cp/mL | NEG | 0/3 | 0/3 | 0/3 |
| Leptospira broomii | G20 | 2.9e6 CFU/mL | NEG | 0/3 | 0/3 | 0/3 |
| Parechovirus type 1 | G21 | 3.39e5 TCID50/mL | NEG | 0/3 | 0/3 | 0/3 |
| Fusobacterium necrophorum | G22 | 6.52e6 CFU/mL | NEG | 0/3 | 0/3 | 0/3 |
| Mycoplasma genitalium c | G23 | 3.6e6 genome cp/mL | NEG | 0/3 | 0/3 | 0/3 |
510(k) Summary
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Image /page/18/Picture/0 description: The image shows the logo for Cepheid, a molecular diagnostics company. Below the logo is the text "Xpert® Xpress CoV-2 plus". The logo consists of the company name in a stylized font, with a blue graphic above it.
Traditional 510(k) Submission
Microorganism in the form of genomic RNA were tested in Tris-EDTA+ ([NH]]>O2) buffer using an assay definition file (ADF) a. without sample preparation.
Rhinovirus, Type 1A was initially tested at 4.5 e4 TCIDsomL in test group G8 using virus lot 325725. It was re-tested b. individually (G16) at a higher concentration of 1.1e5 TCID50/mL using virus lot 326527.
c. Microorganisms in the form of genomic DNA were tested in simulated NPS/NS background matrix using the ADF with full sample preparation.
d. Legionella pneumophila was tested in this study.
Microbial Interference
A microbial interference study was performed to assess the inhibitory effects of commensal microorganisms potentially encountered in upper respiratory tract specimens on the performance of the Xpert Xpress CoV-2 plus test. A panel of 18 commensal microorganisms, consisting of 15 viral strains and 3 bacterial strains was tested. Contrived samples consisted of SARS-CoV-2 virus seeded at 1.15x-3x LoD into simulated nasopharyngeal swab (NPS)/ anterior nasal swab (NS) matrix in the presence of fifteen (15) commensal virus strains and three (3) commensal bacterial strains (Haemophilus influenzae, Staphylococcus aureus, Staphylococcus epidermidis) spiked at their respective concentrations listed in Table 5-11.
Replicates of 8 positive samples were tested with SARS-CoV-2 virus and each potential microbial interference strain combination. All 8 of 8 positive replicate samples were correctly identified as SARS-CoV-2 POSITIVE using the Xpert Xpress CoV-2 plus test. No interference by the listed above commensal viral or bacterial strains was reported at the concentrations tested.
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| Commensal Strain | Concentration
Tested | Number of Correct
Test Results/
Number Tested |
|---------------------------------|-------------------------|-----------------------------------------------------|
| Adenovirus Type 1C a | 1x105 TCID50/mL | 8/8 |
| Adenovirus Type 2C b | 1x105 TCID50/mL | 8/8 c |
| Adenovirus Type 3Bb | 1x105 TCID50/mL | 8/8 |
| Human Coronavirus-OC43 a | 1x105 copies/mL | 8/8 |
| Human Coronavirus-229E b | 1x105 TCID50/mL | 8/8 |
| Human Coronavirus-NL63 b | 1x105 TCID50/mL | 8/8 |
| Human Coronavirus-HKU1b | 1x105 copies/mL | 8/8 |
| Metapneumovirus 5, Type B1 a | 1x105 TCID50/mL | 8/8 |
| Parainfluenza Type 1 a | 1x105 TCID50/mL | 8/8 |
| Parainfluenza Type 2 a | 1x105 TCID50/mL | 8/8 |
| Parainfluenza Type 3 a | 1x105 TCID50/mL | 8/8 |
| Rhinovirus Type 1A a | 1x105 PFU/mL | 8/8 |
| Influenza A H1N1 b | 1x105 CEID50/mL | 8/8 |
| Influenza Bb | 1x105 TCID50/mL | 8/8 d |
| Respiratory Syncytial Virus A b | 1x105 TCID50/mL | 8/8 |
| Haemophilus influenzae a | 1x107 CFU/mL | 8/8 |
| Staphylococcus aureus a | 1x107 CFU/mL | 8/8 |
| Staphylococcus epidermidis a | 1x107 CFU/mL | 8/8 |
Table 5-11: Microbial Interference Study Results
a. These commensal strains were tested with SARS-CoV-2 at a concentration of 3x LoD.
b. These commensal strains were tested with SARS-CoV-2 at a concentration of 1.15x LoD.
c. Two of 8 replicates reported as ERROR. The runs were successfully repeated to obtain 8 valid replicates.
d. One of 8 replicates reported as ERROR. The run was successfully repeated to obtain 8 valid replicates.
Potentially Interfering Substances
Substances that could be present in the nasopharynx (or introduced during specimen collection and handling) and potentially interfere with accurate detection of SARS-CoV-2 were evaluated with direct testing on the Xpert Xpress CoV-2 plus test. Potentially interfering substances in the nasal passage and nasopharynx may include, but are not limited to: blood, nasal secretions or mucus, and nasal and throat medications used to relieve congestion, nasal dryness, irritation, or asthma and allergy symptoms, as well as antibiotics and antivirals. Positive and negative samples were prepared in simulated nasopharyngeal swab (NPS)/ anterior nasal swab (NS) matrix. Negative samples (N = 8) were tested in the presence of each substance to determine the effect on the performance of the sample processing control (SPC). Positive samples (N = 8) were tested per substance with SARS-CoV-2 virus spiked at 3x LoD. The controls were samples with and without SARS-CoV-2 virus spiked at 3x LoD into simulated NPS/ NS matrix containing no potentially interfering substance.
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Image /page/20/Picture/1 description: The image contains the logo for Cepheid, a molecular diagnostics company. The logo features a stylized blue graphic above the company name, "Cepheid." Below the company name is the text "Xpert® Xpress CoV-2 plus", which likely refers to one of Cepheid's diagnostic tests. The text is in a smaller font size than the company name.
The 23 potentially substances, with active ingredients, that were evaluated are listed in Table 5-12. For substances that resulted in an INVALID test result, the concentration of the substance was reduced by half and re-tested. Interfering effects were observed for fluticasone propionate and mucin type I-S.
Substance ID | Substance/Class | Substance/Active Ingredient | Concentrations Tested |
---|---|---|---|
No substance | Control | Simulated NPS/NS Matrix | 100% (v/v) |
Afrin | Nasal Spray | Oxymetazoline (0.05%) | 15% (v/v) |
Albuterol Sulfate | Beta-adrenergic | ||
bronchodilator | Albuterol Sulfate (5mg/mL) | 0.83 mg/mL (equivalent | |
to 1 dose per day) | |||
BD Universal | |||
Transport Medium | Transport Media | BD Universal Transport | |
Medium | 100% (v/v) | ||
Blood | Blood | Blood (Human) | 2% (v/v) |
Copan Swab M | Transport Media | Copan Swab M | 100% (v/v) |
FluMist | FluMist® | Live intranasal influenza virus | |
vaccine | 6.7% (v/v) | ||
Fluticasone Propionate | |||
Nasal Spray | Nasal corticosteroid | Fluticasone Propionate | 5 µg/mL, 2.5 µg/mL |
Ibuprofen | Analgesic (nonsteroidal | ||
anti-inflammatory drugs | |||
(NSAID)) | Ibuprofen | 21.9 mg/dL | |
Leukocytes | Leukocytes | Leukocytes (Human) | 1 x 106 cells/mL |
Menthol | Throat lozenges, oral | ||
anesthetic, and analgesic | Benzocaine, Menthol | 1.7 mg/mL | |
Mucin type II | Mucin | Purified Mucin protein | |
(Porcine submaxillary gland, | |||
type II) | 0.1% (w/v) | ||
Mucin type I-S | Mucin | Purified Mucin protein (Bovine | |
submaxillary gland, type I-S) | 2.5 mg/mL, 1.25 mg/mL | ||
Mupirocin | Antibiotic, nasal ointment | Mupirocin (2%) | 10 mg/mL |
Human peripheral | |||
blood mononuclear | |||
cells (PBMC) | Human peripheral blood | ||
mononuclear cells | |||
(PBMC) | Human peripheral blood | ||
mononuclear cells (PBMC) | 1x103 cells/µL | ||
PHNY | Nasal Drops | Phenylephrine (1%) | 15% (v/v) |
Remel M4RT | Transport Media | Remel M4RT | 100% (v/v) |
Remel M5 | Transport Media | Remel M5 | 100% (v/v) |
Saline | Saline Nasal Spray | Sodium Chloride (0.65%) | 15% (v/v) |
Snuff | Tobacco | Nicotine | 1% (w/v) |
Tamiflu | Anti-viral drugs | Zanamivir | 7.5 mg/mL |
Tobramycin | Antibacterial, systemic | Tobramycin | 4 µg/mL |
Zicam | Nasal Gel | Luffa opperculata, Galphimia | |
glauca, Histaminum | |||
hydrochloricum Sulfur (0.05%) | 15% (w/v) | ||
Zinc | Zinc supplement | Zinc Gluconate | 0.1 µg/mL |
Table 5-12. Potentially Interfering Substances Tested
The results for the negative and positive samples are presented in Table 5-13.
The results from the SARS-CoV-2 negative samples showed that in the presence of fluticasone propionate nasal spray at 5 µg/mL and mucin type I-S at 2.5 mg/mL, 7 of 8 replicates correctly reported "SARS-CoV-2 NEGATIVE" test results, and 1 of 8 replicates reported "INVALID" test result for each substance. When the concentrations of fluticasone
21
propionate nasal spray and mucin type I-S were reduced by half, 8/8 replicates provided valid test results and correctly reported "SARS-CoV-2 NEGATIVE" for each substance. No interference was observed at these lower concentrations.
The results from the SARS-CoV-2 positive samples showed that in the presence of fluticasone propionate nasal spray at 5 µg/mL, 7 of 8 replicates correctly reported "SARS-CoV-2 POSITIVE" test results and 1 of 8 replicate reported "INVALID" test result. When the concentration of the fluticasone propionate nasal spray was reduced to 2.5 µg/mL, 8/8 replicates provided valid test results and correctly reported "SARS-CoV-2 POSITIVE". No interference was observed at this lower concentration.
Table 5-13. SARS-CoV-2 Negative Samples Tested in the Presence of Potentially Interfering Substances
| Substance | Concentration Tested | Number SARS-CoV-2
Negative / Number of Valid
Replicates Tested | Number SARS-CoV-2
Positive / Number of Valid
Replicates Tested |
|----------------------------------------------------|----------------------|----------------------------------------------------------------------|----------------------------------------------------------------------|
| SARS-CoV-2 Negative
(No Substance) Control | 100% (v/v) | 8/8 | Not Applicable |
| SARS-CoV-2 Positive
(No Substance) Control | 100% (v/v) | Not Applicable | 8/8 |
| Afrin | 15% (v/v) | 8/8 | 8/8 |
| Albuterol Sulfate | 0.83 mg/mL | 8/8 | 8/8 |
| BD Universal Transport
Medium | 100 (v/v) | 8/8 | 8/8 |
| Blood | 2% (v/v) | 8/8 | 8/8 |
| Copan Swab M | 100 (v/v) | 8/8 | 8/8 |
| FluMist® | 6.7% (v/v) | 8/8 | 8/8 |
| Fluticasone Propionate Nasal
Spray | 5 µg/mL | 7/8a | 7/8a |
| Ibuprofen | 21.9 mg/dL | 8/8 | 8/8 |
| Leukocytes | 1 x 106 cells/mL | 8/8 | 8/8 |
| Menthol | 1.7 mg/mL | 8/8 | 8/8 |
| Mucin (Type II) | 0.1% (w/v) | 8/8 | 8/8 |
| Mucin (Type I-S) | 1.25 mg/mL | 7/8a | Not Applicable |
| Mupirocin | 10 mg/mL | 8/8 | 8/8 |
| Human Peripheral Blood
Mononuclear Cells (PBMC) | 1 x 103 cells/µL | 8/8 | 8/8 |
| PHNY | 15% (v/v) | 8/8 | 8/8 |
| Remel M4RT | 100% (v/v) | 8/8 | 8/8 |
| Remel M5 | 100% (v/v) | 8/8 | 8/8 |
| Saline | 15% (v/v) | 8/8 | 8/8 |
| Snuff | 1% (w/v) | 8/8 | 8/8 |
| Tamiflu | 7.5 mg/mL | 8/8 | 8/8 |
| Tobramycin | 4 µg/mL | 8/8 | 8/8 |
| Zicam | 15% (w/v) | 8/8 | 8/8 |
| Zinc | 0.1 µg/mL | 8/8 | 8/8 |
a. One of 8 replicates reported INVALID test result, indicating interference from the substance was subsequently tested with 8 replicates at half the initial concentration.
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Image /page/22/Picture/0 description: The image shows the Cepheid logo, which includes a stylized blue graphic above the word "Cepheid." The text below the logo reads "Xpert® Xpress CoV-2 plus". The "Xpert" has a registered trademark symbol next to it.
Carryover Contamination
A study was conducted to assess whether the single-use, self-contained Xpert Xpress CoV-2 plus cartridge prevents specimen and amplicon carryover by testing a negative sample immediately after testing of a very high positive sample in the same GeneXpert module. The negative sample used in this study consisted of simulated NPS/NS matrix and the positive sample consisted of high SARS-CoV-2 virus concentration (inactivated SARS-CoV-2 USA-WA1/2020 at 5e4 copies/mL) spiked into negative NPS/NS matrix. The negative sample was tested in a GeneXpert module at the start of the study. Following the initial testing of the negative sample, the high positive sample was processed in the same GeneXpert module immediately followed by another negative sample. This was repeated 20 times in the same module, resulting in 20 positives and 21 negatives for the module. The study was repeated using a second GeneXpert module for a total of 40 positive and 42 negative samples. All 40 positive samples were correctly reported as SARS-CoV-2 POSITIVE and all 42 negative samples were correctly reported as SARS-CoV-2 NEGATIVE with the Xpert Xpress CoV-2 plus test. No specimen or amplicon carry-over contamination was observed in this study.
Reproducibility
The reproducibility of the Xpert Xpress CoV-2 plus test was established at 3 sites (2 external and 1 internal) using a 3-member panel including one negative sample, one low positive (~1.5x LoD) sample and one moderate positive (~3x LoD) sample. The negative sample consisted of simulated NS/NPS matrix without target microorganism or target RNA. The positive samples were contrived samples in a simulated matrix using inactivated NATtrol SARS-CoV-2 (ZeptoMetrix).
Testing was conducted over 6 days, using 3 lots of Xpert Xpress CoV-2 plus cartridges at 3 participating sites each with 2 operators to yield a total of 144 observations per panel member (3 Sites x 2 Operators x 3 Lots x 2 Days/Lot x 2 Runs x 2 Replicates = 144 observations/panel member).
The percent agreement of the qualitative results for SARS-CoV-2 detection for each panel member analyzed by each of the 6 operators and each site is shown in Table 5-14. In addition, the overall percent agreement for each sample (% total agreement) and the twosided Wilson Score confidence intervals (CI) are presented in the last column.
23
Traditional 510(k) Submission
| Panel
Member | Site 1 | | | Site 2 | | | Site 3 | | | % Total Agreement
and 95% CI by Panel
Member |
|-----------------------|-----------------|------------------|------------------|-----------------|-----------------|-----------------|-----------------|------------------|-----------------|----------------------------------------------------|
| | Op1 | Op2 | Site | Op1 | Op2 | Site | Op1 | Op2 | Site | |
| Negative | 100%
(24/24) | 95.8%
(23/24) | 97.9%
(47/48) | 100%
(24/24) | 100%
(24/24) | 100%
(48/48) | 100%
(24/24) | 100%
(23/23)a | 100%
(47/47) | 99.3% (142/143)
[96.1% - 99.9%] |
| SARS-CoV-2
Low Pos | 100%
(24/24) | 100%
(24/24) | 100%
(48/48) | 100%
(24/24) | 100%
(24/24) | 100%
(48/48) | 100%
(24/24) | 100%
(24/24) | 100%
(48/48) | 100% (144/144)
[97.4% - 100%] |
| SARS-CoV-2
Mod Pos | 100%
(24/24) | 100%
(24/24) | 100%
(48/48) | 100%
(24/24) | 100%
(24/24) | 100%
(48/48) | 100%
(24/24) | 100%
(24/24) | 100%
(48/48) | 100% (144/144)
[97.4% - 100%] |
Table 5-14. Summary of the Reproducibility Results - % Agreement
The evaluation of reproducibility and within-laboratory precision of the underlying Ct values for E, N2 and RdRP obtained in the Xpert Xpress CoV-2 plus test was analyzed. The mean, standard deviation (SD), and coefficient of variation (CV) between-sites, between-operators, between-lots, between-days, between-runs and within-run for each panel member are presented in Table 5-15.
Sample | Analyte | N | Mean Ct | Between Sites | Between Operators | Between Lots | Between Days | Between Runs | Within Run | Total | |||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
SD | CV (%) | SD | CV (%) | SD | CV (%) | SD | CV (%) | SD | CV (%) | SD | CV (%) | SD | CV (%) | ||||
Negative | SPC | 143 | 31.1 | 0.29 | 0.9 | 0.16 | 0.5 | 0.42 | 1.3 | 0 | 0 | 0 | 0 | 1.47 | 4.7 | 1.56 | 5.0 |
SARS-CoV-2 Low Pos | E | 144 | 34.0 | 0.06 | 0.2 | 0.19 | 0.6 | 0 | 0 | 0.14 | 0.4 | 0 | 0 | 0.55 | 1.6 | 0.60 | 1.8 |
N2 | 144 | 37.5 | 0.12 | 0.3 | 0 | 0 | 0.2 | 0.5 | 0.11 | 0.3 | 0 | 0 | 0.68 | 1.8 | 0.73 | 1.9 | |
RdRP | 144 | 36.3 | 0.07 | 0.2 | 0 | 0 | 0.25 | 0.7 | 0.06 | 0.2 | 0 | 0 | 0.61 | 1.7 | 0.66 | 1.8 | |
SARS-CoV-2 Mod Pos | E | 144 | 32.5 | 0.31 | 0.9 | 0.03 | 0.1 | 0 | 0 | 0.47 | 1.4 | 0 | 0 | 1.86 | 5.7 | 1.95 | 6.0 |
N2 | 144 | 36.2 | 0.16 | 0.4 | 0 | 0 | 0.29 | 0.8 | 0.17 | 0.5 | 0 | 0 | 0.65 | 1.8 | 0.75 | 2.1 | |
RdRP | 144 | 34.8 | 0.33 | 1.0 | 0 | 0 | 0 | 0 | 0.62 | 1.8 | 0 | 0 | 2.18 | 6.2 | 2.29 | 6.6 |
Table 5-15. Summary of Reproducibility Results – Nested ANOVA by Coefficient of Variation
510(k) Summary
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Single-Site Precision
The precision of the Xpert Xpress CoV-2 plus test was established at a single site using a 3member panel including one negative sample, one low positive (~1.5x LoD) sample and one moderate positive (~3x LoD) sample. The negative sample consisted of simulated NS/NPS matrix without target microorganism or target RNA. The positive samples were contrived samples in a simulated NS/NPS matrix using inactivated NATtrol SARS-CoV-2 (ZeptoMetrix).
Testing was conducted over 20 days, using one lot of Xpert Xpress CoV-2 plus cartridges at a single site and with 1 operator to yield a total of 80 observations per panel member (1 Site x 1 Operator x 1 Lot x 20 Days x 2 Runs x 2 Replicates = 80 observations/panel member). The results from the study are summarized in Table 5-16.
Panel Member | Agreement | % Total Agreement and 95% CI by Panel Member |
---|---|---|
Negative | 80/80 | 100% |
(95.4%-100.0%) | ||
SARS-CoV-2 Low Positive | 80/80 | 100% |
(95.4%-100.0%) | ||
SARS-CoV-2 Mod Positive | 80/80 | 100% |
(95.4%-100.0%) |
Table 5-16. Summary of the Single-Site Precision Results - % Agreement
5.4.2. Clinical Performance
The clinical performance of the Xpert Xpress CoV-2 plus test was evaluated in a multi-site, observational and method comparison study that included 32 geographically diverse sites in the United States (US). Of the 32 sites, 5 sites participated in specimen collection only, 26 sites performed Xpert testing and specimen collection, and 1 site performed Xpert testing as well as comparator and discrepant testing.
The performance of the Xpert Xpress CoV-2 plus test was evaluated using prospectively collected fresh (98.6%) and frozen (1.4%) clinical nasopharyngeal swab (NPS) and anterior nasal swab (NS) specimens in viral transport medium or universal transport medium. These specimens were collected in 2022 from individuals with signs and symptoms of respiratory tract infection and tested using Xpert Xpress CoV-2 plus side by side with a U.S. FDAcleared molecular respiratory panel that includes SARS-CoV-2, in a randomized and blinded fashion. A total of 4047 specimens (2029 NPS and 2018 NS) were evaluated from individuals with signs and symptoms of respiratory infection. Of these, 60 specimens vielded non-determinate results (INVALID, ERROR, and NO RESULT) with Xpert Xpress CoV-2 plus. Additionally, 237 specimens either yielded non-determinate result, or were not tested per comparator package insert. Therefore, 297 (60 + 237) specimens were excluded, and a total of 3750 (1879 NPS and 1871 NS) specimens that yielded valid results by both Xpert Xpress CoV-2 plus and the U.S. FDA-cleared molecular respiratory panel were included in
25
the clinical performance evaluation. Available demographic data collected from study participants are presented in Table 5-17.
| | NPS
(N=1879) | NS
(N=1871) | Overall
(N=3750) |
|-----------------------------------------------|-----------------|----------------|---------------------|
| Gender | | | |
| Female | 1107 (58.9%) | 1171 (62.6%) | 2278 (60.7%) |
| Male | 772 (41.1%) | 700 (37.4%) | 1472 (39.3%) |
| Age Group (Years) | | | |
| Comparator Result | | | | | | | | |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|----------|----------------------------------|----------|-------|----------------------------------|----------|-------|----------------------------------|----------|-------|
| | | Overall | | | NPS | | | NS | | |
| | | Positive | Negative | Total | Positive | Negative | Total | Positive | Negative | Total |
| Xpert Xpress
CoV-2 plus | Positive | 574 | 55 | 629 | 292 | 28b | 320 | 282 | 27d | 309 |
| | Negative | 11 | 3110 | 3121 | 9a | 1550 | 1559 | 2c | 1560 | 1562 |
| | Total | 585 | 3165 | 3750 | 301 | 1578 | 1879 | 284 | 1587 | 1871 |
| PPA | | 98.1%
(95% CI: 96.7% - 98.9%) | | | 97.0%
(95% CI: 94.4% - 98.4%) | | | 99.3%
(95% CI: 97.5% - 99.8%) | | |
| NPA | | 98.3%
(95% CI: 97.7% - 98.7%) | | | 98.2%
(95% CI: 97.4% - 98.8%) | | | 98.3%
(95% CI: 97.5% - 98.8%) | | |
| NPS: nasopharyngeal swab specimen; NS: anterior nasal swab specimen; PPA: Positive Percent Agreement; NPA: Negative Percent
Agreement; CI: 95% two-sided Confidence Interval | | | | | | | | | | |
| a Discrepant test results based on a U.S. FDA EUA SARS-CoV-2 molecular test: 7/9 SARS-CoV-2 negative; 1/7 SARS-CoV-2 positive; 1/9 invalid. | | | | | | | | | | |
| b Discrepant test results based on a U.S. FDA EUA SARS-CoV-2 molecular test: 8/28 SARS-CoV-2 positive; 19/28 SARS-CoV-2 negative; 1/28 invalid. | | | | | | | | | | |
| c Discrepant test results based on a U.S. FDA EUA SARS-CoV-2 molecular test: 2/2 SARS-CoV-2 negative. | | | | | | | | | | |
| d Discrepant test results based on a U.S. FDA EUA SARS-CoV-2 molecular test: 8/27 SARS-CoV-2 positive; 18/27 SARS-CoV-2 | | | | | | | | | | |
Table 5-18. Xpert Xpress CoV-2 plus Performance Results in Symptomatic Individuals
5.5. Conclusions
negative; 1/27 invalid.
The results of the non-clinical and clinical performance studies summarized above demonstrate that the Xpert Xpress CoV-2 plus test is substantially equivalent to the predicate device.