(144 days)
The Acucy™ Influenza A&B Test for the rapid qualitative detection of influenza A and B is composed of a rapid chromatographic immunoassay for the direct and qualitative detection of influenza A and B viral nucleoprotein antigens from nasal and nasopharyngeal swabs of symptomatic patients that is automatically analyzed on the Acucy Reader. The Acucy Influenza A&B Test is a differentiated test, such that influenza A viral antigens can be distinguished from influenza B viral antigens from a single processed sample using a single Test Cassette. The test is intended for use with the Acucy System as an aid in the diagnosis of influenza A and B viral infections. The test is not intended for the detection of influenza C viruses. Negative test results are presumptive and should be confirmed by viral culture or an FDA-cleared influenza A and B molecular assay. Negative test results do not preclude influenza viral infection and should not be used as the sole basis for treatment or other patient management decisions.
The Acucy™ Influenza A&B Test is a lateral flow immunochromatographic assay in the sandwich immunoassay format. The Acucy Influenza A&B Test consists of a Test Cassette that detects and differentiates influenza A and influenza B viral antigens from a patient sample. The test sample, a nasal swab or nasopharyngeal swab, is processed to extract nucleoproteins by mixing the swab in Acucy Influenza A&B Extraction Buffer. The mixture is then added to the sample well of the Test Cassette. From there, the sample migrates along the membrane surface. If influenza A or B viral antigens are present, they form a complex with mouse monoclonal antibodies to influenza A and/or B nucleoproteins conjugated to colloidal gold. The complex is then bound by a rat anti-influenza A and/or mouse anti-influenza B antibody coated on the nitrocellulose membrane. The Acucy Reader is an optoelectronic instrument that uses a reflectance-based measurement method to evaluate the line signal intensities in the results window of the Test Cassette. The Reader scans the Test Cassette and measures the absorbance intensity by processing the results using method-specific algorithms. The Acucy Reader displays the test results POS (+), NEG (-), or INVALID on the screen. The results can also be automatically printed on the Acucy Printer if this option is selected.
The document describes the performance of the Acucy™ Influenza A&B Test with the Acucy™ System, which is a rapid in-vitro diagnostic test. Here's a breakdown of the acceptance criteria and the study that proves the device meets them:
1. Table of Acceptance Criteria and Reported Device Performance
The document doesn't explicitly list "acceptance criteria" for sensitivity and specificity in a separate table. Instead, it presents the achieved performance, which implicitly serves as the successful outcome of the clinical study. The performance is compared against a Composite Reference.
Here's a table summarizing the reported device performance for the combined nasal and nasopharyngeal swab samples from the clinical study, which are the primary results for overall performance:
| Metric | Influenza A Performance | Influenza B Performance |
|---|---|---|
| Sensitivity | 96.4% (95% CI: 93.1% - 98.2%) | 82.3% (95% CI: 75.6% - 87.4%) |
| Specificity | 96.0% (95% CI: 94.4% - 97.2%) | 98.1% (95% CI: 96.9% - 98.8%) |
Other "Acceptance Criteria" implicitly met through other studies:
| Study Category | Acceptance Criteria (Implicit from Results) | Reported Device Performance |
|---|---|---|
| Reproducibility | High agreement across sites, operators, and days for various concentrations. | Overall Percent Agreement for Influenza A samples (High Negative, Low Positive, Moderate Positive, True Negative) ranged from 98.9% to 100%. Overall Percent Agreement for Influenza B samples (High Negative, Low Positive, Moderate Positive, True Negative) ranged from 98.9% to 100%. |
| Limit of Detection (LoD) | Consistently positive results >95% of the time at specified concentrations. | LoD for Influenza A (H1N1pdm09): 1.41 x 10^1 TCID50/mL. LoD for Influenza A (H3N2): 7.06 x 10^1 TCID50/mL. LoD for Influenza B (Victoria): 2.35 x 10^1 TCID50/mL. LoD for Influenza B (Yamagata): 3.40 x 10^1 TCID50/mL. |
| Analytical Reactivity | All tested influenza A strains yield positive A and negative B results; all influenza B strains yield positive B and negative A results. | All 28 tested influenza A and B strains at or near LoD met this criterion. |
| Analytical Specificity / Cross-Reactivity | No cross-reactivity with tested organisms; no interference with influenza A or B detection from microorganisms or human DNA. | All 41 tested bacterial, viral, fungal organisms and human DNA showed no cross-reactivity or interference. |
| Interfering Substances | No interference observed with common respiratory substances. | No interference observed for any of the 20+ tested substances at specified concentrations. |
| Performance Near Cutoff | Untrained users can accurately interpret and perform the test at and below the LoD. | Agreement for low positive and high negative samples ranged from 96.83% to 100% across multiple sites and operators. |
2. Sample Size Used for the Test Set and Data Provenance
- Sample Size for Test Set:
- Clinical Performance Study: 1003 evaluable nasal or nasopharyngeal swab samples were included in the primary analysis. A total of 1053 subjects were enrolled initially.
- Near Cutoff Study: A panel of 84 samples was tested at each of the three CLIA-waived sites, totaling 252 tests.
- Reproducibility Study: Data for each sample type (e.g., Flu A High Negative) involved 30 replicates per site for 3 sites, totaling 90 replicates per sample type.
- Data Provenance:
- Country of Origin: The clinical study was conducted at sixteen investigational sites across the U.S. ("across the U.S.").
- Retrospective or Prospective: The primary clinical study was prospective, conducted during the 2017-2018 influenza season. The "Assay Cutoff" section mentions a clinical dataset comprised of 1252 "prospectively and retrospectively collected samples" was used for ROC analysis, indicating a mix for cutoff optimization, but the main performance evaluation uses prospective data. The Near Cutoff Study was also prospective, conducted during a "normal testing day" over "non-consecutive days."
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts
The document does not specify the number or qualifications of experts for establishing ground truth for the clinical test set. Instead, it states that the ground truth was established by a "Composite Reference" consisting of:
- Two FDA-cleared molecular influenza A&B assays
- Cell culture
A sample was considered positive or negative if two or three of these comparative reference methods agreed. This implies an objective, laboratory-based ground truth rather than a panel of human expert review.
4. Adjudication Method for the Test Set
The adjudication method for the clinical test set was a Composite Reference approach.
- "A sample was considered positive for influenza A or influenza B by the Composite Reference if two or three of the comparative reference methods gave a positive result."
- "A sample was considered negative for influenza A or influenza B by the composite reference if two or three of the comparative reference methods gave a negative result."
This is a form of 2-out-of-3 or 3-out-of-3 majority vote from the reference methods, ensuring robust ground truth.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done, and the Effect Size of How Much Human Readers Improve with AI vs. Without AI Assistance
This document describes an in vitro diagnostic device (a rapid test and its reading system), not an AI-assisted diagnostic imaging device for human readers. Therefore, an MRMC comparative effectiveness study involving human readers and AI assistance is not applicable and was not performed. The "Acucy Reader" is an optoelectronic instrument that automatically processes the lateral flow test, so human interpretation of the test line is not the primary mechanism of reading.
6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) Was Done
Yes, the primary clinical performance evaluation and all analytical studies (LoD, reactivity, specificity, interfering substances) represent standalone performance of the device (Acucy™ Influenza A&B Test with the Acucy™ System). The Acucy Reader is an automated system that "scans the Test Cassette and measures the absorbance intensity by processing the results using method-specific algorithms" and "displays the test results POS (+), NEG (-), or INVALID on the screen." This is purely algorithm/device driven, without human interpretation of the test lines themselves.
7. The Type of Ground Truth Used (expert consensus, pathology, outcomes data, etc.)
The ground truth used for the clinical performance evaluation was a Composite Reference based on laboratory methods:
- Two FDA-cleared molecular influenza A&B assays
- Cell culture
This is a robust and objective ground truth commonly used for infectious disease diagnostics.
8. The Sample Size for the Training Set
The document describes a 510(k) submission for a diagnostic test kit involving a lateral flow immunoassay and an optical reader. This is a traditional IVD device, not an AI/ML model that typically requires a large "training set" in the machine learning sense.
However, the "Assay Cutoff" section mentions:
- Initial determination using "contrived influenza A samples, influenza B samples, and negative samples prepared in clinical nasal matrix," tested in "replicates of 60 with two lots of reagents (a total of 360 test results)." This internal testing likely contributed to the initial algorithm development or parameter setting.
- "To validate the primary cutoff values, a clinical dataset comprised of 1252 prospectively and retrospectively collected samples was tested with the Acucy Influenza A&B Test, and Receiver Operator Characteristic (ROC) analysis was performed to determine the optimal values for sensitivity and specificity." This dataset of 1252 samples was used for optimizing and validating the assay cutoffs, which is analogous to a development/validation set in an ML context, though not a "training set" in the iterative learning sense.
9. How the Ground Truth for the Training Set Was Established
For the 1252 samples used for ROC analysis and cutoff adjustment:
- The document implies that these samples were "clinical samples," and it's highly probable their true status (positive/negative for Flu A/B) would have been determined by similar reference methods (molecular assays, cell culture) as used for the main clinical study, or other highly accurate laboratory methods.
- For the "contrived samples" used for initial cutoff determination, the ground truth was known by design (i.e., whether the sample was spiked with influenza virus and at what concentration).
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Image /page/0/Picture/0 description: The image contains the logo of the U.S. Food and Drug Administration (FDA). On the left is the Department of Health & Human Services logo. To the right of that is the FDA logo, which consists of the letters "FDA" in a blue square, followed by the words "U.S. FOOD & DRUG ADMINISTRATION" in blue text.
December 17, 2018
Sekisui Diagnostics, LLC Shelly Harris Director of Regulatory Affairs 6659 Top Gun St. San Diego, California 92121
Re: K182001
Trade/Device Name: Acucy Influenza A&B Test with the Acucy System Regulation Number: 21 CFR 866.3328 Regulation Name: Influenza virus antigen detection test system Regulatory Class: Class II Product Code: PSZ Dated: July 25, 2018 Received: July 26, 2018
Dear Shelly Harris:
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 (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 located 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.
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 803) for devices or postmarketing safety reporting (21 CFR 4, Subpart B) for combination products (see
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https://www.fda.gov/CombinationProducts/GuidanceRegulatoryInformation/ucm597488.html; good manufacturing practice requirements as set forth in the quality systems (OS) regulation (21 CFR Part 820) for devices or current good manufacturing practices (21 CFR 4, Subpart A) for combination products; and, if applicable, the electronic product radiation control provisions (Sections 531-542 of the Act); 21 CFR 1000-1050.
Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21 CFR Part 807.97). For questions regarding the reporting of adverse events under the MDR regulation (21 CFR Part 803), please go to http://www.fda.gov/MedicalDevices/Safety/ReportaProblem/default.htm.
For comprehensive regulatory information about mediation-emitting products, including information about labeling regulations, please see Device Advice (https://www.fda.gov/MedicalDevices/DeviceRegulationandGuidance/) and CDRH Learn (http://www.fda.gov/Training/CDRHLearn). 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 (http://www.fda.gov/DICE) for more information or contact DICE by email (DICE@fda.hhs.gov) or phone (1-800-638-2041 or 301-796-7100).
Sincerely,
for
Uwe Scherf, Ph.D. Director Division of Microbiology Devices Office of In Vitro Diagnostics and Radiological Health Center for Devices and Radiological Health
Enclosure
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Indications for Use
510(k) Number (if known)
Device Name
Indications for Use (Describe)
Prescription Use (Part 21 CFR 801 Subpart D)
| Over-The-Counter Use (21 CFR 801 Subpart C)
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510(k) Summary of Safety and Effectiveness
This 510(k) summary of safety and effectiveness is being submitted in accordance with the requirements of SMDA 1990 and 21 CFR 807.92.
The assigned 510(k) number is: K182001
Sponsor/Applicant Name and Address 1.
| Company Name: | Sekisui Diagnostics, LLC |
|---|---|
| Address: | 6659 Top Gun StreetSan Diego, CA 92121 |
Telephone: 858-777-2627 Contact Person: Shelly Harris
Date Summary Prepared: 11/08/2018
2. Device Name and Classification
Trade Name: Acucy™ Influenza A&B Test with the Acucy™ System Classification of Device: 21 CFR 866.3328, Influenza virus antigen detection test system Product Code: PSZ
3. Predicate Device
K112177, K131606, K153012: Quidel Sofia® Analyzer and Influenza A+B FIA
4. Device Description
Operating Principle
The Acucy™ Influenza A&B Test is a lateral flow immunochromatographic assay in the sandwich immunoassay format. The Acucy Influenza A&B Test consists of a Test Cassette that detects and differentiates influenza A and influenza B viral antigens from a patient sample. The test sample, a nasal swab or nasopharyngeal swab, is processed to extract nucleoproteins by mixing the swab in Acucy Influenza A&B Extraction Buffer. The mixture is then added to the sample well of the Test Cassette. From there, the sample migrates along the membrane surface. If influenza A or B viral antigens are present, they form a complex with mouse monoclonal antibodies to influenza A and/or B nucleoproteins conjugated to colloidal gold. The complex is then bound by a rat anti-influenza A and/or mouse anti-influenza B antibody coated on the nitrocellulose membrane.
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The Acucy Reader is an optoelectronic instrument that uses a reflectance-based measurement method to evaluate the line signal intensities in the results window of the Test Cassette. The Reader scans the Test Cassette and measures the absorbance intensity by processing the results using method-specific algorithms. The Acucy Reader displays the test results POS (+), NEG (-), or INVALID on the screen. The results can also be automatically printed on the Acucy Printer if this option is selected.
Acucy™ Influenza A&B Test Kit Contents
The Acucy Influenza A&B Test Kit contains all the materials needed to run a test, except for the Acucy Reader, which is provided separately. The Acucy Influenza Test Kit contains the following components:
- 25 Acucy Influenza A&B Test Cassettes (+ 2 for external quality control testing) ●
- 25 Sterile Nasal Swabs
- 25 Acucy Influenza A&B Extraction Buffer Vials (+ 2 for external quality control ● testing)
- 25 Extraction Buffer Vial Dropper Tips (+ 2 for external quality control testing)
- 1 Influenza A Positive Control Swab ●
- 1 Influenza B Positive Control Swab
- 1 Instructions for Use (IFU) ●
- 1 Quick Reference Guide (READ NOW and WALK AWAY/NORMAL Modes) ●
- 1 External Quality Control (QC) Quick Reference Guide
- 1 Acucy System Calibration Procedure Quick Reference Guide .
- . 1 Workstation
The Acucy Reader is provided with an Acucy Printer, power cords and adapters, paper roll, Acucy Calibration Device with case, USB Memory Drive, and System Manual.
5. Indications for Use
The Acucy™ Influenza A&B Test for the rapid qualitative detection of influenza A and B is composed of a rapid chromatographic immunoassay for the direct and qualitative detection of influenza A and B viral nucleoprotein antigens from nasal and nasopharyngeal swabs of symptomatic patients that is automatically analyzed on the Acucy Reader. The Acucy Influenza A&B Test is a differentiated test, such that influenza A viral antigens can be distinguished from influenza B viral antigens from a single processed sample using a single Test Cassette. The test is intended for use with the Acucy System as an aid in the diagnosis of influenza A and B viral infections. The test is not intended for the detection of influenza C viruses. Negative test results are presumptive and should be confirmed by viral culture or an FDA-cleared influenza A and B molecular assay. Negative test results do not preclude influenza viral infection and should not be used as the sole basis for treatment or other patient management decisions.
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Performance characteristics for influenza A were established during the 2017-2018 influenza season when influenza A/H3N2 and A/H1N1pdm09 were the predominant influenza A viruses in circulation. When other influenza A viruses are emerging, performance characteristics may vary.
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 department for testing. Viral culture should not be attempted in these cases unless a BSL 3+ facility is available to receive and culture specimens.
Comparison to Predicate Device 6.
The following table provides a comparison of the characteristics of the Acucy Influenza A&B Test with the Acucy System to the predicate device, the Quidel Sofia Analyzer and Influenza A+B FIA: K112177, K1131606, and K153012.
| Similarities | ||
|---|---|---|
| Item | 510(k) Device:Acucy™ Influenza A&B Testwith the Acucy™ System | Predicate Device:Sofia® Analyzer and InfluenzaA+B FIAK112177 |
| Indications for Use | The Acucy™ Influenza A&B Test for the rapid qualitative detection of influenza A and B is composed of a rapid chromatographic immunoassay for the direct and qualitative detection of influenza A and B viral nucleoprotein antigens from nasal and nasopharyngeal swabs of symptomatic patients that is automatically analyzed on the Acucy Reader. The Acucy Influenza A&B Test is a differentiated test, such that influenza A viral antigens can be distinguished from influenza B viral antigens from a single processed sample using a single device. The test is intended for use with the Acucy System as an aid in the diagnosis of influenza A and B viral infections. The test is not intended for the detection of influenza C viruses. | The Sofia Influenza A+B FIA employs immunofluorescence to detect influenza A and influenza B viral nucleoprotein antigens in nasal swab, nasopharyngeal swab, and nasopharyngeal aspirate/wash specimens taken directly from symptomatic patients. This qualitative test is intended for use as an aid in the rapid differential diagnosis of acute influenza A and influenza B viral infections. The test is not intended to detect influenza C antigens. A negative test is presumptive and it is recommended these results be confirmed by virus culture or an FDA-cleared influenza A and B molecular assay. Negative results do not preclude influenza virus infections and should not be used as the sole basis for treatment or other management |
| Negative test results arepresumptive and should beconfirmed by viral culture or anFDA-cleared influenza A and Bmolecular assay. Negative testresults do not preclude influenzaviral infection and should not beused as the sole basis fortreatment or other patientmanagement decisions.Performance characteristics forinfluenza A were establishedduring the 2017-2018 influenzaseason when influenza A/H3N2and A/H1N1pdm09 were thepredominant influenza A virusesin circulation. When otherinfluenza A viruses areemerging, performancecharacteristics may vary.If infection with a novelinfluenza A virus is suspectedbased on current clinical andepidemiological screeningcriteria recommended by publichealth authorities, specimensshould be collected withappropriate infection controlprecautions for novel virulentinfluenza viruses and sent tostate or local health departmentfor testing. Viral culture shouldnot be attempted in these casesunless a BSL 3+ facility isavailable to receive and culturespecimens. | decisions. The test is intendedfor professional and laboratoryuse.Performance characteristics forinfluenza A and B wereestablished during Februarythrough March 2011 wheninfluenza virusesA/California/7//2009 (2009H1N1), A/Perth/16/2009(H3N2), and B/Brisbane/60/2008(Victoria-Like) were thepredominant influenza viruses incirculation according to theMorbidity and Mortality WeeklyReport from the CDC entitled"Update: Influenza Activity –United States, 2010-2011Season, and Composition of the201102012 Influenza Vaccine".Performance characteristics mayvary against other emerginginfluenza viruses.If infection with a novelinfluenza virus is suspectedbased on current clinical andepidemiological screeningcriteria recommended by publichealth authorities, specimensshould be collected withappropriate infection controlprecautions for novel virulentinfluenza viruses and sent tostate or local health departmentfor testing. Virus culture shouldnot be attempted in these casesunless a BSL 3+ facility isavailable to receive and culturespecimens. | |
| Assay Results | Qualitative | Same |
| Assay Targets | Influenza A and B antigens | Same |
| Assay Format | Lateral flow test cassette | Same |
| Sample Types | Nasal swab; nasopharyngealswab | Nasal swab, nasopharyngealswab; nasopharyngealaspirate/wash |
| AssayAntibodies | Monoclonal antibodies toinfluenza A and Bnucleoproteins | Same |
| Sample TransferMethod | Dropper tip applied to extractiontube to transfer extracted sample | Fixed volume pipet used totransfer extracted sample |
| Reporting ofResults | Reader displays results onscreen; or may be printed | Same |
| Time to Result | 15 minutes | Same |
| InstrumentModes | Read Now or WalkAway/Normal | Same |
| Intended Usersand UseLocations | Clinical laboratory and point ofcare | Same |
| Calibrator | Yes - QC verification cassetteprovided | Yes - Calibration cassette andQC card provided |
| StorageTemperature | Room Temperature | Same |
| Assay Controls | Internal procedural control | Same |
| InstrumentQuality ControlFeatures | Scanning procedural controlzone for adequate flow•Reader prevents use of usedcassettes•Reader prevents use ofexpired cassettes•Prevents improper cassetteinsertion• | Same |
| Test Principle | Immunochromatographic device | Immunofluorescence device |
| InstrumentDetectionMethod | Absorbance | Fluorescence |
| ExternalControls | • Influenza A Positive/BNegative Control• Influenza B Positive/ANegative Control | • Positive InfluenzaA/Influenza B Control• Negative Control |
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7. Performance Summary
Expected Values
The prevalence of influenza varies from year to year, with outbreaks occurring during the fall and winter months. The influenza positivity rate is dependent upon many factors, including specimen collection, test method, and geographic location. Prevalence varies throughout the influenza season and from location to location.
The Sekisui Diagnostics prospective clinical study was conducted during the 2017-2018 influenza season. The following tables show the positivity rates of influenza A and influenza B as determined by the Acucy Influenza A&B Test in three subject age categories in that clinical study. The overall positivity rate observed during the 2017-2018 U.S. clinical study, based on 1003 evaluable nasal or nasopharyngeal swab samples, was 24.6% for influenza A and 14.6% for influenza B.
| Flu A Positivity Rate forNasal & Nasopharyngeal Swab Samples | |||
|---|---|---|---|
| Age Group | Number of Specimens | Number of Flu APositives | Flu A PositivityRate |
| ≤ 5 Years of Age | 326 | 84 | 25.8% |
| 6 to 21 Years of Age | 406 | 130 | 32.0% |
| ≥ 22 Years of Age | 271 | 33 | 12.2% |
| Total | 1003 | 247 | 24.6% |
Flu A Positives by the Acucy™ Influenza A&B Test by Age Group
Flu B Positives by the Acucy™ Influenza A&B Test by Age Group
| Flu B Positivity Rate forNasal & Nasopharyngeal Swab Samples | |||
|---|---|---|---|
| Age Group | Number of Specimens | Number of Flu BPositives | Flu B PositivityRate |
| ≤ 5 Years of Age | 326 | 36 | 11.0% |
| 6 to 21 Years of Age | 406 | 76 | 18.7% |
| ≥ 22 Years of Age | 271 | 34 | 12.5% |
| Total | 1003 | 146 | 14.6% |
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Clinical Performance
A prospective, multi-center study was conducted to evaluate the performance of the Acucy Influenza A&B Test for the detection of influenza A and influenza B in nasopharyngeal and nasal swabs from patients with signs and symptoms of influenza. The study was conducted during the 2017-2018 influenza season at sixteen investigational sites across the U.S. The study was performed in point-of-care (POC) locations, such as physician office laboratories, urgent care, and outpatient clinics. The Acucy Influenza A&B Test was compared to a Composite Reference, consisting of two FDA cleared molecular influenza A&B assays and cell culture. A sample was considered positive for influenza A or influenza B by the Composite Reference if two or three of the comparative reference methods gave a positive result. A sample was considered negative for influenza A or influenza B by the composite reference if two or three of the comparative reference methods gave a negative result. A total of 1053 subjects were enrolled in the study, and of those, 1003 were considered evaluable. Comparison with the Composite Reference method is summarized in the following tables. Sensitivity, specificity and 95% confidence intervals are reported. Results are shown for nasal swabs, nasopharyngeal swabs, and both swab types combined.
| Acucy™ Influenza | Composite Reference | ||
|---|---|---|---|
| A&B TestFlu A | Positive | Negative | Total |
| Positive | 216 | 31 | 247 |
| Negative | 8 | 748 | 756 |
| Total | 224 | 779 | 1003 |
| Sensitivity | 96.4% (95% CI: 93.1% - 98.2%) | ||
| Specificity | 96.0% (95% CI: 94.4% - 97.2%) |
Acucy™ Influenza A&B Test Influenza A Performance Against the Composite Reference Nasal and Nasonharyngeal Swahs
Acucy™ Influenza A&B Test Influenza B Performance Against the Composite Reference Nasal and Nasopharyngeal Swabs
| Acucy™ InfluenzaA&B TestFlu B | Composite Reference | ||
|---|---|---|---|
| Positive | Negative | Total | |
| Positive | 130 | 16 | 146 |
| Negative | 28 | 829 | 857 |
| Total | 158 | 845 | 1003 |
| Sensitivity | 82.3% (95% CI: 75.6% - 87.4%) | ||
| Specificity | 98.1% (95% CI: 96.9% - 98.8%) |
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| Acucy™ InfluenzaA&B TestFlu A | Composite Reference | ||
|---|---|---|---|
| Positive | Negative | Total | |
| Positive | 96 | 16 | 112 |
| Negative | 4 | 379 | 383 |
| Total | 100 | 395 | 495 |
| Sensitivity | 96.0% (95% CI: 90.2% - 98.4%) | ||
| Specificity | 95.9% (95% CI: 93.5% - 97.5%) |
Acucy™ Influenza A&B Test Influenza A Performance Against the Composite Reference N 1 ડ
Acucy™ Influenza A&B Test Influenza B Performance Against the Composite Reference Nasal Swabs
| Acucy™ InfluenzaA&B TestFlu B | Composite Reference | ||
|---|---|---|---|
| Positive | Negative | Total | |
| Positive | 61 | 9 | 70 |
| Negative | 14 | 411 | 425 |
| Total | 75 | 420 | 495 |
| Sensitivity | 81.3% (95% CI: 71.1% - 88.5%) | ||
| Specificity | 97.9% (95% CI: 96.0% - 98.9%) |
Acucy™ Influenza A&B Test Influenza A Performance Against the Composite Reference Nasopharyngeal Swabs
| Acucy™ InfluenzaA&B TestFlu A | Composite Reference | ||
|---|---|---|---|
| Positive | Negative | Total | |
| Positive | 120 | 15 | 135 |
| Negative | 4 | 369 | 373 |
| Total | 124 | 384 | 508 |
| Sensitivity | 96.8% (95% CI: 92.0% - 98.7%) | ||
| Specificity | 96.1% (95% CI: 93.7% - 97.6%) |
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| Acucy™ InfluenzaA&B TestFlu B | Composite Reference | ||
|---|---|---|---|
| Positive | Negative | Total | |
| Positive | 69 | 7 | 76 |
| Negative | 14 | 418 | 432 |
| Total | 83 | 425 | 508 |
| Sensitivity | 83.1% (95% CI: 73.7% - 89.7%) | ||
| Specificity | 98.4% (95% CI: 96.6% - 99.2%) |
Acucy™ Influenza A&B Test Influenza B Performance Against the Composite Reference Nasopharyngeal Swabs
Reproducibility Studies
The reproducibility of the Acucy Influenza A&B Test was evaluated in testing performed at three point of care (POC) sites. A panel of swabs including true negative (no virus), high negative (below the limit of detection), low positive (at or near the limit of detection) and moderate positive (at or near 2x the limit of detection) for influenza A (H3N2) and B were coded, randomized, and masked to the operators. The study was conducted with two operators per site over five non-consecutive days. As seen in the table below, the Acucy Influenza A&B Test produces reproducible results when tested by multiple intended users, at multiple sites, over multiple days.
| Reproducibility Results by Site - Influenza A: Counts and Percent Agreement | ||||
|---|---|---|---|---|
| Sample | Site 1 | Site 2 | Site 3 | Overall PercentAgreement and95% CI |
| Influenza A High Negative | 100%(30/30) | 100%(30/30) | 96.7%(29/30) | 98.9%(94.0%-99.8%) |
| Influenza A Low Positive | 100%(30/30) | 100%(30/30) | 100%(30/30) | 100%(95.9%-100%) |
| Influenza A Moderate Positive | 100%(30/30) | 100%(30/30) | 100%(30/30) | 100%(95.9%-100%) |
| True Negative | 100%(30/30) | 100%(30/30) | 100%(30/30) | 100%(95.9%-100%) |
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| Reproducibility Results by Site - Influenza B: Counts and Percent Agreement | ||||
|---|---|---|---|---|
| Sample | Site 1 | Site 2 | Site 3 | Overall Percent Agreement and 95% CI |
| Influenza B High Negative | 100%(30/30) | 100%(30/30) | 100%(30/30) | 100%(95.9%-100%) |
| Influenza B Low Positive | 100%(30/30) | 100%(30/30) | 100%(30/30) | 100%(95.9%-100%) |
| Influenza B Moderate Positive | 100%(30/30) | 100%(30/30) | 96.7%(29/30) | 98.9%(94.0-99.8) |
| True Negative | 100%(30/30) | 100%(30/30) | 100%(30/30) | 100%(95.9%-100%) |
Analytical Sensitivity: Limit of Detection
The limit of detection (LoD) for the Acucy Influenza A&B Test was established in dilution studies performed with two influenza A strains and two influenza B strains on two lots of the Acucy Influenza A&B Test. The LoD represents the concentration of influenza virus that produces consistently positive results >95% of the time. The approximate LoD concentrations identified for each strain tested are listed in the table below.
| Limit of Detection | |||
|---|---|---|---|
| Strain | Type | Subtype | LoDTCID50/mL |
| A/California/07/09 pdm | A | H1N1pdm09 | $1.41x10^1$ |
| A/Hong Kong/4801/14 | A | H3N2 | $7.06x10^1$ |
| B/Brisbane/60/08 | B | Victoria | $2.35x10^1$ |
| B/Phuket/3073/13 | B | Yamagata | $3.40x10^1$ |
Analytical Reactivity
A total of 28 influenza A and B strains were tested with the Acucy Influenza A&B Test, at levels at or near the assay LoD. All influenza A virus isolates gave positive A and negative B results. All influenza B virus isolates gave negative A and positive B results.
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| Analytical Reactivity | ||||
|---|---|---|---|---|
| Strain | ConcentrationTCID50/mL | Type | Subtype | TestResult |
| A/NY/02/09 | 1.06x102 | A | H1N1pdm09 | Detected |
| A/Mexico/4108/09 | 1.06x102 | A | H1N1pdm09 | Detected |
| A/PR/8/34 | 1.06x102 | A | H1N1 | Detected |
| A/Singapore/63/04 | 2.04x103 | A | H1N1 | Detected |
| A/Taiwan/42/06 | 1.02x103 | A | H1N1 | Detected |
| A/Canada/6294/09 | 2.12x103 | A | H1N1pdm09 | Detected |
| A/New Cal/20/99 | 1.06x102 | A | H1N1 | Detected |
| A/Solomon Islands/03/06 | 1.06x102 | A | H1N1 | Detected |
| A/NY/01/09 | 1.06x102 | A | H1N1pdm09 | Detected |
| A/NY/03/09 | 1.06x102 | A | H1N1pdm09 | Detected |
| A/Brisbane/59/07 | 1.06x102 | A | H1N1 | Detected |
| A/Brisbane/10/07 | 1.06x102 | A | H3N2 | Detected |
| A/Victoria/361/11 | 1.06x102 | A | H3N2 | Detected |
| A/HK/8/68 | 1.06x102 | A | H3N2 | Detected |
| A/Perth/16/09 | 1.06x102 | A | H3N2 | Detected |
| A/Wisconsin/67/05 | 1.06x102 | A | H3N2 | Detected |
| A/Rhode Island/01/2010 | 5.00x105 | A | H3N2 | Detected |
| A/New York/55/2004 | 2.00x105 | A | H3N2 | Detected |
| A/Florida/2/2006 | 3.30x105 | A | H3N2 | Detected |
| A/Texas/50/2012 | 1.06x102 | A | H3N2 | Detected |
| A/Texas/71/2007 | 4.08x103 | A | H3N2 | Detected |
| A/Indiana/08/2011 | 5.30x102 | A | H3N2v | Detected |
| B/Malaysia/2506/04 | 5.10x101 | B | B | Detected |
| B/Massachusetts/2/12 | 5.10x102 | B | B | Detected |
| B/Wisconsin/1/10 | 5.10x101 | B | B | Detected |
| B/Texas/6/11 | 7.24x102 | B | B | Detected |
| B/Florida/07/04 | 2.55x102 | B | B | Detected |
| A/Anhui/1/2013 | 1.00x108 | A | A (Avian) | Detected |
Analytical Specificity: Cross-Reactivity and Microbial Interference
The Acucy Influenza A&B Test was evaluated with 41 organisms (bacterial, viral, fungal) and Human DNA. Bacterial isolates were tested at concentrations of approximately10° colony forming units per mL (cfu/mL) or color changing units per mL (CCU/mL). Viral isolates were tested at approximately 105 plaque forming units per mL (pfu/mL), copies/mL, or tissue culture infectious dose 50% per mL (TCID50/mL). No cross-reactivity was observed at the concentrations tested as all of the microorganisms tested produced negative responses for influenza A and B. No interference toward the detection of influenza A analyte or influenza B analyte was observed from all microorganisms and human genomic DNA at the concentrations tested.
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| Potentially Cross-Reacting Bacterial | Potentially Cross-Reacting Non-Influenza |
|---|---|
| and Fungal Isolates | Virus Strain and Human DNA |
| Bordetella pertussis | Adenovirus type 1 |
| Candida albicans | Adenovirus type 7A |
| Chlamydia pneumoniae | Human coronavirus |
| Escherichia coli | Enterovirus |
| Haemophilus influenzae | Coxsackie virus |
| Klebsiella pneumoniae | Cytomegalovirus |
| Lactobacillus acidophilus Z048 | Epstein Barr virus (EBV) |
| Legionella pneumoniae | Parainfluenza type 1 |
| Moraxella catarrhalis | Parainfluenza type 2 |
| Mycoplasma hominis | Parainfluenza type 3 |
| Mycobacterium tuberculosis | Measles virus |
| Mycoplasma pneumoniae | Human metapneumovirus 3 type B1 |
| Neisseria meningitidis | Human metapneumovirus 9 type A1 |
| Neisseria gonorrhoeae | Human herpes virus 6 (HHV6), Z29 |
| Pseudomonas aeruginosa | Human herpes virus 7 (HHV7), SB |
| Staphylococcus aureus MRSA | Mumps virus |
| Staphylococcus aureus MSSA | Respiratory syncytial virus type A2 |
| Staphylococcus epidermidis MRSE | Respiratory syncytial virus type B |
| Streptococcus pneumoniae | Rhinovirus |
| Streptococcus pyogenes | Human genomic DNA |
| Streptococcus salivarius | |
| Corynebacterium ulcerans |
Assay Cutoff
The assay cutoffs (thresholds of detection) for influenza A and influenza B were initially determined by testing contrived influenza A samples, influenza B samples, and negative samples prepared in clinical nasal matrix. Samples were tested in replicates of 60 with two lots of reagents (a total of 360 test results).
To validate the primary cutoff values, a clinical dataset comprised of 1252 prospectively and retrospectively collected samples was tested with the Acucy Influenza A&B Test, and Receiver Operator Characteristic (ROC) analysis was performed to determine the optimal values for sensitivity and specificity. The assay cutoffs were adjusted slightly based on this ROC analysis.
The Acucy Influenza A&B Test also employs a secondary cutoff in the event that one analyte (influenza A or B) is present in the sample at a very high titer. High titer samples have been shown to generate higher levels of non-specific binding at the for the second analyte. Use of the secondary cutoff prevents reporting of a false positive result for the second analyte. This cutoff was validated by testing high titer samples of one analyte mixed with varying concentrations of the second analyte and testing with the Acucy Influenza A&B Test. Ten different mixtures of influenza A and influenza B samples were tested in replicates of 20. The validation demonstrated the effectiveness of the secondary cutoff in preventing false positive results caused by high titer samples.
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Interfering Substances
The Acucy Influenza A&B Test was evaluated with potential interferents that may be encountered in respiratory specimens. The substances were tested at the concentrations listed in the table below. No interference was observed with the test for any of the substances at the concentrations tested.
| Substance | Potential Interferent | Concentration |
|---|---|---|
| No substance control | Dry swab | N/A |
| Control | Viral transport media (VTM) | N/A |
| Mucus (Bovine) | Mucin protein | 19 mg/mL |
| Whole blood | Whole blood with EDTA | 5% v/v |
| Tylenol | Acetaminophen | 0.1 mg/mL |
| NSAIDS | Aspirin | 16.2 mg/mL |
| Ibuprofen | 40 mg/mL | |
| Naproxen | 110 mg/mL | |
| Nasal Corticosteroids | Dexamethasone (injection) | 3 mg/mL |
| Dexamethasone (oral) | 0.5 mg/mL | |
| Fluticasone | 50 µg/mL | |
| Mometasone furoate | 2.5 µg/mL | |
| Budesonide | 25 µg/mL | |
| Flunisolide | 68.75 µg/mL | |
| Nasal Sprays | Triamcinolone acetonide | 5.5 µg/mL |
| Beclomethasone | 16 µg/mL | |
| Oxymetazoline | 0.025% v/v | |
| Phenylephrine | 0.5% v/v | |
| Sodium chloride | 0.325% v/v | |
| Nasal Gel | Galphima glauca, Luffa operculate | 4x,4x |
| Antiviral | Oseltamivir | 5 mg/mL |
| Antibacterial, systemic | Tobramycin | 40.0 µg/mL |
| Throat Lozenges | Benzocaine | 2.5% soln. |
| Antibiotic Nasal Ointment | Mupirocin | 0.15 mg/mL |
| Allergy Medicine | Histaminum hydrochloricum | 1% solution |
CLIA Waiver Studies
Clinical Performance by Intended Users
The performance of the Acucy Influenza A&B Test was evaluated at 16 intended use sites by non-laboratory personnel in a prospective clinical study during the 2017-2018 influenza season in the U.S. Nasal or nasopharyngeal swabs were collected from patients with flu-like symptoms and were tested with the Acucy Influenza A&B Test and the reference methods. Results were compared to a compostite reference, which was calculated from the results of three reference methods: two molecular methods and cell culture. Results for nasal and nasopharyngeal swabs combined are shown in the following tables.
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| Acucy™ InfluenzaA&B TestFlu A | Composite Reference | ||
|---|---|---|---|
| Positive | Negative | Total | |
| Positive | 216 | 31 | 247 |
| Negative | 8 | 748 | 756 |
| Total | 224 | 779 | 1003 |
| Sensitivity | 96.4% (95% CI: 93.1% - 98.2%) | ||
| Specificity | 96.0% (95% CI: 94.4% - 97.2%) |
Acucy™ Influenza A&B Test Influenza A Performance Against the Composite Reference Nasal and Nasopharyngeal Swabs
Acucy™ Influenza A&B Test Influenza B Performance Against the Composite Reference Nasal and Nasopharyngeal Swabs
| Acucy™ InfluenzaA&B TestFlu B | Composite Reference | ||
|---|---|---|---|
| Positive | Negative | Total | |
| Positive | 130 | 16 | 146 |
| Negative | 28 | 829 | 857 |
| Total | 158 | 845 | 1003 |
| Sensitivity | 82.3% (95% CI: 75.6% - 87.4%) | ||
| Specificity | 98.1% (95% CI: 96.9% - 98.8%) |
Performance Near the Cutoff
Three CLIA-waived sites that participated in the prospective clinical study participtated in the Near Cutoff Study. The testing was performed by three untrained intended operators at each of the sites. This study was conducted to demonstrate that untrained users could perform the Acucy Influenza A&B Test and consistently detect samples at the limit of detection (LoD).
The test panel consisted of four contrived samples applied to nasal swabs: a low positve influenza A sample at 1x LoD, a high negative influenza A sample at 0.1 x LoD, a low positive influenza B sample at 1x LoD, and a high negative influenza B sample at 0.25 LoD. low positive samples are expected to give a positive result, and high negative samples are expected to give a negative result.
Samples were masked as subject samples and were presented to the intended use operators for testing throughout the course of a normal testing day. Testing took place over the course of two weeks on non-consecutive days. Each operator tested seven samples each testing day. Each site ultimately tested a panel of 84 samples.
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The test results are summarized in the table below. The study demonstrates that untrained intended use operators are able to accurately perform and interpret the Acucy Influenza A&B Test at and below the level of the LoD for both influenza A and influenza B.
| Sample Type | ||||
|---|---|---|---|---|
| Site | Low PositiveA | Low PositiveB | High NegativeA | High NegativeB |
| 1 | 21/21 | 20/21 | 21/21 | 20/21 |
| 2 | 21/21 | 20/21 | 21/21 | 21/21 |
| 3 | 21/21 | 21/21 | 21/21 | 21/21 |
| Total | 63/63 | 61/63 | 63/63 | 62/63 |
| Agreement | 100% | 96.83% | 100% | 98.41% |
Near Cutoff Study Test Results: Percent Agreement of Observed/Expected Values
8. Conclusion
The information presented in this Premarket Notification demonstrates that the performance of the Acucy Influenza A&B Test with the Acucy System is substantially equivalent in intended use, technological characteristics, and performance to the predicate device.
§ 866.3328 Influenza virus antigen detection test system.
(a)
Identification. An influenza virus antigen detection test system is a device intended for the qualitative detection of influenza viral antigens directly from clinical specimens in patients with signs and symptoms of respiratory infection. The test aids in the diagnosis of influenza infection and provides epidemiological information on influenza. Due to the propensity of the virus to mutate, new strains emerge over time which may potentially affect the performance of these devices. Because influenza is highly contagious and may lead to an acute respiratory tract infection causing severe illness and even death, the accuracy of these devices has serious public health implications.(b)
Classification. Class II (special controls). The special controls for this device are:(1) The device's sensitivity and specificity performance characteristics or positive percent agreement and negative percent agreement, for each specimen type claimed in the intended use of the device, must meet one of the following two minimum clinical performance criteria:
(i) For devices evaluated as compared to an FDA-cleared nucleic acid based-test or other currently appropriate and FDA accepted comparator method other than correctly performed viral culture method:
(A) The positive percent agreement estimate for the device when testing for influenza A and influenza B must be at the point estimate of at least 80 percent with a lower bound of the 95 percent confidence interval that is greater than or equal to 70 percent.
(B) The negative percent agreement estimate for the device when testing for influenza A and influenza B must be at the point estimate of at least 95 percent with a lower bound of the 95 percent confidence interval that is greater than or equal to 90 percent.
(ii) For devices evaluated as compared to correctly performed viral culture method as the comparator method:
(A) The sensitivity estimate for the device when testing for influenza A must be at the point estimate of at least 90 percent with a lower bound of the 95 percent confidence interval that is greater than or equal to 80 percent. The sensitivity estimate for the device when testing for influenza B must be at the point estimate of at least 80 percent with a lower bound of the 95 percent confidence interval that is greater than or equal to 70 percent.
(B) The specificity estimate for the device when testing for influenza A and influenza B must be at the point estimate of at least 95 percent with a lower bound of the 95 percent confidence interval that is greater than or equal to 90 percent.
(2) When performing testing to demonstrate the device meets the requirements in paragraph (b)(1) of this section, a currently appropriate and FDA accepted comparator method must be used to establish assay performance in clinical studies.
(3) Annual analytical reactivity testing of the device must be performed with contemporary influenza strains. This annual analytical reactivity testing must meet the following criteria:
(i) The appropriate strains to be tested will be identified by FDA in consultation with the Centers for Disease Control and Prevention (CDC) and sourced from CDC or an FDA-designated source. If the annual strains are not available from CDC, FDA will identify an alternative source for obtaining the requisite strains.
(ii) The testing must be conducted according to a standardized protocol considered and determined by FDA to be acceptable and appropriate.
(iii) By July 31 of each calendar year, the results of the last 3 years of annual analytical reactivity testing must be included as part of the device's labeling. If a device has not been on the market long enough for 3 years of annual analytical reactivity testing to have been conducted since the device received marketing authorization from FDA, then the results of every annual analytical reactivity testing since the device received marketing authorization from FDA must be included. The results must be presented as part of the device's labeling in a tabular format, which includes the detailed information for each virus tested as described in the certificate of authentication, either by:
(A) Placing the results directly in the device's § 809.10(b) of this chapter compliant labeling that physically accompanies the device in a separate section of the labeling where the analytical reactivity testing data can be found; or
(B) In the device's label or in other labeling that physically accompanies the device, prominently providing a hyperlink to the manufacturer's public Web site where the analytical reactivity testing data can be found. The manufacturer's home page, as well as the primary part of the manufacturer's Web site that discusses the device, must provide a prominently placed hyperlink to the Web page containing this information and must allow unrestricted viewing access.
(4) If one of the actions listed at section 564(b)(1)(A)-(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 (HHS) 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 viral samples in accordance with a standardized protocol considered and determined by FDA to be acceptable and appropriate. The procedure and location of testing may depend on the nature of the emerging virus.
(ii) Within 60 days from the date that FDA notifies manufacturers that characterized 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 § 809.10(b) of this chapter compliant labeling that physically 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 physically accompanies the device, prominently providing a hyperlink to the manufacturer's public Web site where the analytical reactivity testing data can be found. The manufacturer's home page, as well as the primary part of the manufacturer's Web site that discusses the device, must provide a prominently placed hyperlink to the Web page containing this information and must allow unrestricted viewing access.