(204 days)
Sofia 2 Campylobacter FIA employs immunofluorescence for the rapid qualitative detection of a Campylobacter-specific antigen in human fecal specimens. Sofia 2 Campylobacter FIA is designed to detect C. jejuni, C. coli, C. lari and C. upsalients with signs and symptoms of gastroenteritis. The test is intended for use with preserved fecal specimens in transport media and unpreserved fecal specimens. Test results should be considered in conjunction with clinical findings and patient history.
The Sofia 2 Campylobacter FIA employs immunofluorescence technology that is used with Sofia 2 for the rapid qualitative detection of Campylobacter jejuni, Campylobacter lari, and Campylobacter upsaliensis specific antigens in fecal samples.
The patient's sample is placed in the Specimen Tube containing the Specimen Solution to dilute, making the antigenic components more accessible to the specific antibodies. An aliquot of the diluted sample is dispensed through a filter to remove particulates, making them more compatible for testing, into the Test Cassette sample well. From the sample well, the sample migrates through a test strip containing various unique chemical environments. If Campylobacter jejuni, Campylobacter coli, Campylobacter lari, or Campylobacter upsaliensis specific antigens are present, they will be bound by antibodies coupled to fluorescent microparticles that migrate through the test strip. The fluorescent microparticles containing bound proteins will be captured by antibodies at a defined location on the test strip where they are detected by Sofia 2. If Campylobacter jejuni, Campylobacter coli, Campylobacter lari, or Campylobacter upsaliensis specific antigens are not present, the fluorescent microparticles will not be trapped by the capture antibodies nor detected by Sofia 2.
The Test Cassette is placed inside of Sofia 2 for automatically timed development (WALK AWAY Mode), or pre-incubated on the bench top prior to loading into Sofia 2 (READ NOW Mode), where Sofia 2 will scan, measure, and interpret the immunofluorescent signal using method-specific algorithms. Sofia 2 will display the test results (Positive, Negative, or Invalid) on the screen.
The fluorescence signal obtained with this assay is invisible to the unaided eye. The test results can only be obtained with the proper use of Sofia 2.
The Sofia 2 Campylobacter FIA is a device for the rapid qualitative detection of Campylobacter-specific antigens. It is designed to detect C. jejuni, C. coli, C. lari, and C. upsaliensis from patients with signs and symptoms of gastroenteritis in human fecal specimens (preserved or unpreserved).
Here's an analysis of the acceptance criteria and the study data provided:
1. Table of Acceptance Criteria and Reported Device Performance
Based on the provided information, the key performance metrics are Sensitivity and Specificity from the Prospective Clinical Study.
| Acceptance Criteria | Reported Device Performance (95% CI) |
|---|---|
| Sensitivity | 100% (67.6% to 100%) |
| Specificity | 99.3% (98.4% to 99.7%) |
2. Sample size used for the test set and the data provenance
- Test Set Sample Size for Clinical Study: 811 total specimens.
- 191 fresh, neat specimens
- 620 fresh specimens in transport media
- Data Provenance: Prospective Clinical Study (likely multi-center, though specific countries are not mentioned). All specimens were "fresh".
- Test Set Sample Size for Archived Study: 70 frozen, characterized specimens.
- 35 culture-negative specimens preserved in transport media.
- 35 positive specimens (11 in transport media, 24 neat fecal specimens).
- Data Provenance for Archived Study: Archived, frozen specimens, characterized at a central laboratory.
3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts
The document does not specify the number of experts or their qualifications for establishing the ground truth.
4. Adjudication method for the test set
- For the Prospective Clinical Study: The primary comparison was against culture and identification. For discordant specimens (Sofia Positive/Culture Negative), species-specific RT-PCR and bi-directional sequence analysis were used for confirmation. In this case, 6 discordant specimens were identified as positive for Campylobacter (3 C. jejuni, 2 C. upsaliensis, and 1 C. coli) by this additional molecular testing. This suggests a form of discordant analysis/adjudication.
- For the Archived Clinical Study: Ground truth was established by culture and further characterized by RT-PCR and bi-directional sequencing. All 35 positive specimens were confirmed by all methods, and all 35 negative specimens yielded 100% correlation with all test methods.
5. If a multi reader multi case (MRMC) comparative effectiveness study was done, If so, what was the effect size of how much human readers improve with AI vs without AI assistance
This is not applicable as the Sofia 2 Campylobacter FIA is an automated IVD device. It does not involve human readers interpreting results with or without AI assistance in the context of diagnostic imaging, for example. The Sofia 2 instrument scans, measures, and interprets the immunofluorescent signal using method-specific algorithms and displays the result.
6. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done
Yes, the device operates in a standalone manner. The Sofia 2 instrument itself provides the final "Positive, Negative, or Invalid" result after processing the test cassette. This performance directly reflects the algorithm's output. The performance data (Sensitivity, Specificity) from the clinical studies represents this standalone performance.
7. The type of ground truth used (expert consensus, pathology, outcomes data, etc.)
- Prospective Clinical Study: Culture and identification was the primary reference method. For discordant results (Sofia Positive/Culture Negative), species-specific RT-PCR and bi-directional sequence analysis were used as a confirmatory ground truth.
- Archived Clinical Study: Culture for initial characterization, and further confirmed by RT-PCR and bi-directional sequencing.
8. The sample size for the training set
The document does not explicitly state the sample size used for the training set of the device's algorithms. The provided data focuses on the validation of the finalized device.
9. How the ground truth for the training set was established
The document does not provide details on how the ground truth for the training set was established. It focuses on the analytical and clinical validation of the device.
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November 23, 2021
Quidel Corporation Michelle Bodien Director, Regulatory Affairs 10165 McKellar Court San Diego, California 92121
Re: K211342
Trade/Device Name: Sofia 2 Campylobacter FIA Regulation Number: 21 CFR 866.3110 Regulation Name: Campylobacter fetus Serological Reagents Regulatory Class: Class I. reserved Product Code: LQP, KHO Dated: April 30, 2021 Received: May 3, 2021
Dear Michelle Bodien:
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
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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 https://www.fda.gov/combination-products/guidance-regulatory-information/postmarketing-safety-reportingcombination-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 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 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,
Ribhi Shawar, Ph.D. (ABMM) Chief General Bacteriology and Antimicrobial Susceptibility Branch Division of Microbiology Devices OHT7: Office of In Vitro Diagnostics and Radiological Health Office of Product Evaluation and Quality 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)
| Type of Use (Select one or both, as applicable) | |
|---|---|
| ------------------------------------------------- | -- |
Prescription Use (Part 21 CFR 801 Subpart D)
| Over-The-Counter Use (21 CFR 801 Subpart C)
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510(k) Summary
Submitter
Ouidel Corporation 10165 McKellar Court San Diego, CA 92121 Telephone: (800) 874-1517
Submission Contact
Michelle Bodien Director, Regulatory Affairs (210) 740-5756
Date Prepared
November 22, 2021
Proprietary and Established Names
Sofia 2 Campylobacter FIA
Common Name
Campylobacter spp. rapid test
Classification
| Product Code | Classification | Regulatory Section | Description |
|---|---|---|---|
| LQP | 1 | 21 CFR 866.3110 | Campylobacter spp. |
Panel
Microbiology
Predicate Device
CAMPYLOBACTER QUIK CHEK™ (K191456)
Device Description
The Sofia 2 Campylobacter FIA employs immunofluorescence technology that is used with Sofia 2 for the rapid qualitative detection of Campylobacter jejuni, Campylobacter lari, and Campylobacter upsaliensis specific antigens in fecal samples.
The patient's sample is placed in the Specimen Tube containing the Specimen Solution to dilute, making the antigenic components more accessible to the specific antibodies. An aliquot of the diluted sample is dispensed through a filter to remove particulates, making them more compatible for testing, into the Test Cassette sample well. From the sample well, the sample migrates through a test strip containing various unique chemical environments. If Campylobacter jejuni, Campylobacter coli, Campylobacter lari, or Campylobacter upsaliensis specific antigens are present, they will be bound by antibodies coupled to fluorescent microparticles that migrate through the test strip. The fluorescent microparticles containing bound proteins will be captured by antibodies at a defined location on the test strip where they are detected
Sofia 2 Campylobacter FIA 510(k)
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by Sofia 2. If Campylobacter jejuni, Campylobacter coli, Campylobacter lari, or Campylobacter upsaliensis specific antigens are not present, the fluorescent microparticles will not be trapped by the capture antibodies nor detected by Sofia 2.
The Test Cassette is placed inside of Sofia 2 for automatically timed development (WALK AWAY Mode), or pre-incubated on the bench top prior to loading into Sofia 2 (READ NOW Mode), where Sofia 2 will scan, measure, and interpret the immunofluorescent signal using method-specific algorithms. Sofia 2 will display the test results (Positive, Negative, or Invalid) on the screen.
The fluorescence signal obtained with this assay is invisible to the unaided eye. The test results can only be obtained with the proper use of Sofia 2.
Intended Use
Sofia 2 Campylobacter FIA employs immunofluorescence for the rapid qualitative detection of a Campylobacter-specific antigen in human fecal specimens. Sofia 2 Campylobacter FIA is designed to detect C. jejuni, C. coli, C. lari and C. upsalients with signs and symptoms of gastroenteritis. The test is intended for use with preserved fecal specimens in transport media and unpreserved fecal specimens. Test results should be considered in conjunction with clinical findings and patient history.
| Features | Proposed DeviceSofia 2 Campylobacter FIA | Predicate DeviceCAMPYLOBACTER QUIK CHEKTM(K191456) |
|---|---|---|
| Intended Use | Sofia 2 Campylobacter FIA employsimmunofluorescence for the rapidqualitative detection of aCampylobacter -specific antigen inhuman fecal specimens. Sofia® 2Campylobacter FIA is designed todetect C. jejuni, C. coli, C. lari and C.upsaliensis from patients with signs andsymptoms of gastroenteritis. The test isintended for use with preserved fecalspecimens in transport media andunpreserved fecal specimens. Testresults should be considered inconjunction with clinical findings andpatient history. | The CAMPYLOBACTER QUIKCHEK test is a rapid membraneenzyme-linked immunosorbent assayfor the qualitative detection of aCampylobacter -specific antigen inhuman fecal specimens. TheCAMPYLOBACTER QUIK CHEKtest is designed to detect C. jejuni, C.coli, C. lari , and C. upsaliensis frompatients with signs and symptoms ofgastroenteritis. The test is intended foruse with preserved fecal specimens intransport media and unpreserved fecalspecimens. Test results should beconsidered in conjunction withclinical findings and patient history. |
| AutomatedAnalysis | Yes | No |
| Qualitative | Yes | Same |
| Analyte | Campylobacter -specific antigens ( C.jejuni, C. coli, C. lari and C.upsaliensis ) | Same |
Comparison with Predicate
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| Features | Proposed DeviceSofia 2 Campylobacter FIA | Predicate DeviceCAMPYLOBACTER QUIK CHEKTM(K191456) |
|---|---|---|
| Specimen Type | Human fecal specimens (unpreserved)or preserved in Cary Blair and C&STransport Media | Same |
| Test Principle | Immunofluorescence device | Immunosorbent assay |
| Format | Lateral-flow test cassette | Membrane Enzyme LinkedImmunosorbent Assay (ELISA) |
| Antibodies Used | Monoclonal and polyclonal antibodiesthat are specific to Campylobacterantigen | Same |
| External Controls | Test kit contains Positive(Campylobacter-specific antigen) andNegative Control Solutions | Same |
| Time to Result | 15 minutes | <30 minutes |
| Storage | Room Temperature (15°C - 30°C) | Refrigerated (2°C - 8°C) |
Performance Data
Numerous studies were undertaken to document the performance characteristics and the substantial equivalence of the test to the predicate device. Key studies include the following:
Limit of Detection
The limit of detection (LoD) for Sofia 2 Campylobacter FIA was determined for four Campylobacter species in fecal matrix and in Cary Blair and C&S transport media. The LoD ranged from 9.82 x 104 to 5.21 x 10 colony forming units (cfu)/mL in fecal matrix, 1.57 x 10 cfu/mL in Cary Blair medium, and 1.50 x 105 to 2.71x 106 cfu/mL in C&S medium (Table 1).
| CampylobacterSpecies | Minimum Detectable Limit* | ||
|---|---|---|---|
| Fecal Matrixcfu/mL | Cary Blaircfu/mL | C&Scfu/mL | |
| C. jejuni | $9.82 x 10^4$ | $1.57 x 10^5$ | $1.50 x 10^5$ |
| C. coli | $1.15 x 10^6$ | $1.59 x 10^6$ | $9.02 x 10^5$ |
| C. lari | $2.00 x 10^6$ | $1.75 x 10^6$ | $2.25 x 10^6$ |
| C. upsaliensis | $5.21 x 10^6$ | $5.21 x 10^6$ | $2.71 x 10^6$ |
| Table 1. Limits of Detection | |||
|---|---|---|---|
| -- | -- | -- | ------------------------------ |
cfu/mL = colony forming units per milliliter
*The levels of bacteria were determined by limiting dilution, bacterial culture, and colony counting to give cfu/mL.
Inclusivity (Analytical Reactivity)
Analytical reactivity for Sofia 2 Campylobacter FIA was demonstrated using 17 additional strains of Campylobacter, including clinical isolates. Each strain was spiked into negative fecal matrix at 2-3x the
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LoD of the corresponding reference strain used to confirm the LoD. At 2-3x LoD, samples were at concentrations ranging from 2.95 x 106 to 1.44 x 107 colony forming units (cfu)/mL (Table 2).
| Campylobacter species | Strain | Level Detected* |
|---|---|---|
| Campylobacter jejuni | CCUG 6951 | 2.95 x 105 cfu/mL |
| CCUG 12081 | 2.95 x 105 cfu/mL | |
| CCUG 29411 | 2.95 x 105 cfu/mL | |
| CCUG 38106 | 2.95 x 105 cfu/mL | |
| Campylobacter jejuni subspecies doylei | CCUG 24567 | 2.95 x 105 cfu/mL |
| Campylobacter coli | CCUG 10956 | 3.45 x 106 cfu/mL |
| CCUG 17755 | 3.45 x 106 cfu/mL | |
| CCUG36994 | 3.45 x 106 cfu/mL | |
| CCUG 53138 | 3.45 x 106 cfu/mL | |
| Campylobacter lari | 2015/2189 | 6.00 x 106 cfu/mL |
| 2015/1657 | 6.00 x 106 cfu/mL | |
| 2015/2983 | 6.00 x 106 cfu/mL | |
| 2016/1130H | 6.00 x 106 cfu/mL | |
| Campylobacter upsaliensis | 2016/1950 | 1.44 x 107 cfu/mL |
| 2016/2826 | 1.44 x 107 cfu/mL | |
| 2017/0349 | 1.44 x 107 cfu/mL | |
| 2018/1669 | 1.44 x 107 cfu/mL |
Table 2. Analytical Reactivity
cfu/mL = colony forming units per milliliter
*The levels of bacteria were determined by limiting dilution, bacterial culture, and colony counting to give cfu/mL.
Additional inclusivity testing was performed for select strains of C. coli, C. lari, and C. upsaliensis to verify the lowest concentration of each strain that is reactive in the Sofia 2 Campylobacter FIA. Four-fold serial dilutions for each of the targeted strains were prepared from stock culture slurries using negative fecal matrix and tested in replicates of three in the assay. The qualitative results were used to determine the lowest detectable level in the series, where 3/3 results were positive (Table 3). The results demonstrated that these strains produced positive results in the assay at concentrations below the limit of detection established with the corresponding reference strains. Note: these results are not a true limit of detection and are used to demonstrate inclusivity of these strains at low concentrations of bacteria only.
Table 3. Dilution Testing - Inclusivity Strains
| Species Tested | Dilution | Concentration(cfu/mL) | N | Pos | Neg | % Pos. |
|---|---|---|---|---|---|---|
| Campylobacter coliCCUG 53138Stock $2.2 x 10^7$CFU/mL | Stock slurry | $2.2 x 10^7$ | 3 | 3 | 0 | 100 |
| 1:4 | $5.5 x 10^6$ | 3 | 3 | 0 | 100 | |
| 1:16 | $1.375 x 10^6$ | 3 | 3 | 0 | 100 | |
| 1:64 | $3.438 x 10^5$ | 3 | 3 | 0 | 100 | |
| 1:256 | $8.594x 10^4$ | 3 | 3 | 0 | 100 | |
| 1:1024 | $2.148 x 10^4$ | 3 | 0 | 3 | 0 |
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| Species Tested | Dilution | Concentration(cfu/mL) | N | Pos | Neg | % Pos. |
|---|---|---|---|---|---|---|
| 1:4096 | $5.371 x 10^3$ | 3 | 0 | 3 | 0 | |
| Campylobacter lari2015/2189Stock 1.55 x 107CFU/mL | Stock slurry | $1.55 x 10^7$ | 3 | 3 | 0 | 100 |
| 1:4 | $3.875 x 10^6$ | 3 | 3 | 0 | 100 | |
| 1:16 | $9.688 x 10^5$ | 3 | 3 | 0 | 100 | |
| 1:64 | $2.422 x 10^5$ | 3 | 3 | 0 | 100 | |
| 1:256 | $6.055 x 10^4$ | 3 | 3 | 0 | 100 | |
| 1:1024 | $1.514 x 10^4$ | 3 | 0 | 3 | 0 | |
| 1:4096 | $3.784 x 10^3$ | 3 | 0 | 3 | 0 | |
| Campylobacter lari2016/1130HStock 1.4 x 107CFU/mL | Stock slurry | $1.4 x 10^7$ | 3 | 3 | 0 | 100 |
| 1:4 | $3.5 x 10^6$ | 3 | 3 | 0 | 100 | |
| 1:16 | $8.75 x 10^5$ | 3 | 3 | 0 | 100 | |
| 1:64 | $2.188 x 10^5$ | 3 | 3 | 0 | 100 | |
| 1:256 | $5.469 x 10^4$ | 3 | 0 | 3 | 0 | |
| 1:1024 | $1.367 x 10^4$ | 3 | 0 | 3 | 0 | |
| 1:4096 | $3.418 x 10^3$ | 3 | 0 | 3 | 0 | |
| Campylobacterupsaliensis2016/1950Stock 8.4 x 107CFU/mL | Stock slurry | $8.4 x 10^7$ | 3 | 3 | 0 | 100 |
| 1:4 | $2.1 x 10^7$ | 3 | 3 | 0 | 100 | |
| 1:16 | $5.25 x 10^6$ | 3 | 3 | 0 | 100 | |
| 1:64 | $1.313 x 10^6$ | 3 | 3 | 0 | 100 | |
| 1:256 | $3.281 x 10^5$ | 3 | 2 | 1 | 67 | |
| 1:1024 | $8.203 x 10^4$ | 3 | 0 | 3 | 0 | |
| 1:4096 | $2.051 x 10^4$ | 3 | 0 | 3 | 0 |
Cross Reactivity/Microbial Interference,
The cross reactivity of the Sofia 2 Campylobacter FIA was evaluated with a total of 48 bacterial and fungal microorganisms and 24 viral isolates. None of the microorganisms or viruses showed cross reactivity in the assay at the concentrations tested with the exception of Campylobacter helveticus. Additional C. helveticus concentrations were tested and cross-reactivity was no longer observed at 1.98x105 CFU/mL. For microbial interference testing, the same microorganisms and viruses were pre-mixed with C. jejuni at 2-3x LoD and tested in the assay. None showed any signs of microbial interference in the assay.
Interfering Substances
Several prescription and over-the-counter (OTC) products and endogenous substances were evaluated with the Sofia 2 Campylobacter FIA. Each substance was tested in the presence and absence of C. jejuni at 2-3x LoD. None of the substances interfered with the assay at the levels tested.
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Specimen Storage and Stability
The results of this study demonstrated that neat, unpreserved fecal specimens were stable for up to 96 hours when stored refrigerated (2°C to 8°C) or at room temperature (15°C to 30°C) or up to 13 days when frozen (< - 10°C) prior to use in the Sofia 2 Campylobacter FIA. Specimens stored in Thermo Scientific Protocol™ Cary Blair or Thermo Scientific Protocol™ C&S transport media were stable for up to 96 hours prior to use when refrigerated (2℃ to 8℃) or at room temperature (15℃ to 30℃).
An additional study determined that fecal specimens stored at -10℃ are stable up to four freeze-thaw cycles prior to use in the Sofia 2 Campylobacter FIA.
Hook Effect / High Analyte Concentration
To ensure that a high concentration of Campylobacter antigen does not interfere with a positive reaction in the Sofia 2 Campylobacter FIA, high positive samples were prepared by spiking a negative fecal pool at a concentration possibly observed in clinical specimens. A total of 5 different dilutions of C. jejuni, C. coli, C. lari, and C. upsaliensis whole organism culture preparation, up to and including the clinically observed high concentration, were prepared and tested in triplicate. The results demonstrated that high analyte concentrations did not affect the detection of the antigen.
Precision
This study evaluated the within laboratory precision/repeatability of the Sofia 2 Campylobacter FIA at three (3) different levels of C. jejuni concentrations. Testing was performed for one (1) run per day and 4 replicates per run over twenty (20) non-consecutive days. A total of 240 replicates per level were tested (Table 4).
| Lot | Concentration | # Negative | # Positive | ExpectedResult | PercentAgreement | 95% C.I. |
|---|---|---|---|---|---|---|
| 1 | Negative | 80 | 0 | Negative | 100% | 95.4% to 100% |
| 1-2X C95 | 0 | 80 | Positive | 100% | 95.4% to 100% | |
| 2-3X C95 | 0 | 80 | Positive | 100% | 95.4% to 100% | |
| 2 | Negative | 80 | 0 | Negative | 100% | 95.4% to 100% |
| 1-2X C95 | 0 | 80 | Positive | 100% | 95.4% to 100% | |
| 2-3X C95 | 0 | 80 | Positive | 100% | 95.4% to 100% | |
| 3 | Negative | 80 | 0 | Negative | 100% | 95.4% to 100% |
| 1-2X C95 | 0 | 80 | Positive | 100% | 95.4% to 100% | |
| 2-3X C95 | 0 | 80 | Positive | 100% | 95.4% to 100% |
| Table 4. Summary of Precision Qualitative Results | |||
|---|---|---|---|
| -- | -- | -- | --------------------------------------------------- |
Reproducibility
The reproducibility of the Sofia 2 Campylobacter FIA was evaluated at 3 different laboratories using two product lots. Two different operators at each site tested a series of coded, contrived samples, prepared in negative clinical matrix, ranging from negative (no bacteria) to moderate positive (2-3 x LOD) levels of C. iejuni. Testing was conducted over 5 consecutive days. The inter-laboratory agreement (Table 5) for negative samples was 100% and 100% for positive samples.
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| Site | Negative*(C 0) | High Negative*(0.5-1X C 5) | Low Positive**(1-2X C 95) | Moderate Positive**(2-3X C 95) | ||||
|---|---|---|---|---|---|---|---|---|
| Lot 1 | Lot 2 | Lot 1 | Lot 2 | Lot 1 | Lot 2 | Lot 1 | Lot 2 | |
| 1 | 30/30 | 30/30 | 30/30 | 30/30 | 30/30 | 30/30 | 30/30 | 30/30 |
| 2 | 30/30 | 30/30 | 30/30 | 30/30 | 30/30 | 30/30 | 30/30 | 30/30 |
| 3 | 30/30 | 30/30 | 30/30 | 30/30 | 30/30 | 30/30 | 30/30 | 30/30 |
| Total | 180/180 | 180/180 | 180/180 | 180/180 | ||||
| % OverallAgreement(95% CI) | 100%(97.9% to 100%) | 100%(97.9% to 100%) | 100%(97.9% to 100%) | 100%(97.9% to 100%) |
| Table 5. Reproducibility Study Inter- Laboratory Agreement | |||
|---|---|---|---|
*Bacteria not detected/total
**Bacteria detected/total
Prospective Clinical Study
The performance of the Sofia 2 Campylobacter FIA was compared to culture and identification in a multicenter prospective clinical study. One hundred ninety-one (191) fresh, neat specimens and six hundred twenty (620) fresh specimens in transport media were evaluated. Sixty-two percent (62%) of the subjects were female and thirty-eight percent (38%) were male. Subjects ranged in age between 2 years to over 60 years. The results of the prospective clinical study are shown in Table 6. The eight (8) consensus positive specimens (Sofia Positive/ Culture Positive) were identified as Campylobacter jejuni by species-specific RT-PCR and bi-directional sequence analysis. Of the six (6) discordant specimens (Sofia Positive/ Culture Negative), three specimens were identified as positive for C. jejuni, two were C. upsaliensis, and one was C. coli by species-specific RT-PCR and bi-directional sequence analysis.
| Table 6. Sofia 2 Campylobacter FIA Performance Compared to Culture with Fresh Specimens | |||
|---|---|---|---|
| Culture | |||||
|---|---|---|---|---|---|
| Pos | Neg | Total | Sensitivity = 100% (8/8) | (95% CI=67.6% to 100%) | |
| Sofia Pos | 8 | 6% | 14 | Specificity = 99.3% (797/803) | |
| Sofia Neg | 0 | 797 | 797 | (95% CI=98.4% to 99.7%) | |
| Total: | oc | 803 | 811 |
- Of the 6 culture negative - Sofia 2 Campylobacter FIA positive samples, all 6 were confirmed as positive by species-specific RT-PCR and bi-directional sequence analysis.
Archived Clinical Study
Seventy (70) frozen, characterized specimens were tested by the Sofia 2 Campylobacter FIA at a central laboratory including 35 culture-negative specimens preserved in transport media. Of the 35 positive specimens, there were a total of 11 specimens in transport media and 24 neat fecal specimens. The positive specimens were Campylobacter spp. culture-positive and were further characterized by RT-PCR and bi-directional sequencing to assess if weak positives were included in the archived study and determine performance of the Sofia 2 Campylobacter FIA with such specimens All 35 specimens tested
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positive for Campylobacter spp. by all methods, vielding 100% correlation with all test methods. Thirty specimens were identified as positive for C. jejuni and five were C. coli. Additionally, all 35 negative specimens yielded 100% correlation with all test methods.
Rare Isolates Testing
A study was conducted to evaluate the performance of the Sofia 2 Campylobacter FIA with less common analytes not represented during the clinical studies. Five (5) strains of each species of C. coli, C. lari, and C. upsaliensis were prepared at concentrations of 1-2 times the limit of detection of the corresponding reference strains in neat fecal matrix in Cary Blair transport medium, and fecal matrix in C&S transport medium and tested in the assay over a period of three days. Each strain was detected by the assay with >90% positivity (Table 7). Additionally, a negative sample was prepared in each matrix and tested in parallel, and the expected negative results were obtained each day.
| ConcentrationTested (CFU/mL) | n | Number of Negatives and Positives | % Positivity | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Sample | Day 1 | Day 2 | Day 3 | Day1 | Day2 | Day3 | Total | |||||
| # Neg | # Pos | # Neg | # Pos | # Neg | # Pos | |||||||
| Fecal Matrix | ||||||||||||
| Negative | N/A | 30 | 30 | 0 | 30 | 0 | 30 | 0 | 0 | 0 | 0 | 0 |
| C. coli | 2.30 x 10^6 | 30 | 0 | 30 | 0 | 30 | 0 | 30 | 100 | 100 | 100 | 100 |
| C. lari | 4.00 x 10^6 | 30 | 0 | 30 | 0 | 30 | 0 | 30 | 100 | 100 | 100 | 100 |
| C. upsaliensis | 9.58 x 10^6 | 30 | 0 | 30 | 0 | 30 | 0 | 30 | 100 | 100 | 100 | 100 |
| Cary Blair | ||||||||||||
| Negative | N/A | 30 | 30 | 0 | 30 | 0 | 30 | 0 | 0 | 0 | 0 | 0 |
| C. coli | 3.06 x 10^6 | 30 | 0 | 30 | 0 | 30 | 0 | 30 | 100 | 100 | 100 | 100 |
| C. lari | 3.50 x 10^6 | 30 | 1 | 29 | 0 | 30 | 0 | 30 | 97 | 100 | 100 | 99 |
| C. upsaliensis | 5.20 x 10^6 | 30 | 0 | 30 | 0 | 30 | 0 | 30 | 100 | 100 | 100 | 100 |
| C&S | ||||||||||||
| Negative | N/A | 30 | 30 | 0 | 30 | 0 | 30 | 0 | 0 | 0 | 0 | 0 |
| C. coli | 1.80 x 10^6 | 30 | 0 | 30 | 0 | 30 | 0 | 30 | 100 | 100 | 100 | 100 |
| C. lari | 2.50 X 10^6 | 30 | 0 | 30 | 0 | 30 | 0 | 30 | 100 | 100 | 100 | 100 |
| C. upsaliensis | 4.66 x 10^6 | 30 | 0 | 30 | 0 | 30 | 0 | 30 | 100 | 100 | 100 | 100 |
Table 7 Sofia 2 Campylobacter FIA Performance With Rare Isolates
§ 866.3110
Campylobacter fetus serological reagents.(a)
Identification. Campylobacter fetus serological reagents are devices that consist of antisera conjugated with a fluorescent dye used to identifyCampylobacter fetus from clinical specimens or cultured isolates derived from clinical specimens. The identification aids in the diagnosis of diseases caused by this bacterium and provides epidemiological information on these diseases.Campylobacter fetus is a frequent cause of abortion in sheep and cattle and is sometimes responsible for endocarditis (inflammation of certain membranes of the heart) and enteritis (inflammation of the intestines) in humans.(b)
Classification. Class I (general controls).