(83 days)
Vstrip® H.pylori Antigen Rapid Test is a single use immunochromatographic assay for the qualitative detection of H. pylori antigen in unpreserved human stool specimens. Test results are intended to aid in the initial diagnosis and treatment of H. pylori infection. Test results should be taken into consideration by the physician in conjunction with the patient history and symptoms.
The Vstrip® H.pylori Antigen Rapid Test (Vstrip®) is a Helicobacter pylori (H. pylori) antigen rapid test. It is a lateral flow immunochromatographic assay which employs antibody-coated latex beads to detect H. pylori antigens in stool specimens from patients suspected of H. pylori infection. This test is an in vitro diagnostic device to be used for the qualitative detection of H. pylori antigen in human stool samples, and test results are intended to aid in the diagnosis and treatment of H. pylori infection. This test utilizes a pair of H. pylori-specific monoclonal antibodies that are capable of detecting H.pylori antigens in human stool. The assay kit includes a foil pouch containing test cassette which houses a strip incorporated with a pair of H. pylori-specific monoclonal antibodies, sample preparation tubes that contain sample diluent buffer for dilution of stool sampler tool attached to the underside of the tube cap and a dispenser tool attached to the top of the tube, positive control reagent containing inactivated H.pylori, and the package insert and instructions. Each diagnostic strip is enclosed in a plastic frame with a window to display the results. To perform the test, a diluted stool sample which is first prepared by a sample preparation tube is added to the Test Cassette. If the sample contains H.pylori antigen, a pink-red test to the letter T) along with a blue control line (next to the letter C) will be visible in the rectangle "Result Window", as depicted in Figure 1. A blue control line is a line to show that adequate flow of the sample has occurred and active components have been employed during a test run. The presence of the blue line at the control position on the device confirms that the device is working properly. If H. pylori antigen is absent or below the level of detection, no pink-red line will appear in the rectangle "Result Window" of the cassette next to the letter T, but a distinct blue line shows next to the letter C, as depicted in Figure 1. For invalid result, no visible blue line in the rectangle "Result Window" of the cassette next to the letter C, with or without a visually detectable pink-red line, as depicted in Figure 1. It may occur with the deteriorated materials, but an excess of stool sample and incorrect procedure is mostly the main reason for control line failure. When an invalid result appears, review the test procedure and re- test same specimen. If the test fails again, repeat the test with different specimens. If the problem persists, the use of concerned test kit lot should be discontinued.
Here's a breakdown of the acceptance criteria and the study proving the device meets them, based on the provided text:
Device: Vstrip® H.pylori Antigen Rapid Test
Indication for Use: Single use immunochromatographic assay for the qualitative detection of H. pylori antigen in unpreserved human stool specimens. Test results are intended to aid in the initial diagnosis and treatment of H. pylori infection.
1. Table of Acceptance Criteria and Reported Device Performance
The core performance evaluation for the device relies on a "Comparison Study" against an FDA-cleared H. pylori stool antigen ELISA. The acceptance criteria for this study are specified in the last paragraph of the "Comparison Study" section: "The study acceptance criteria were met." While the specific numerical targets for the acceptance criteria aren't explicitly stated in a standalone table, they are implied by the performance of the comparator ELISA, which was previously evaluated with "a demonstrated sensitivity and specificity greater than or equal to 95% and a lower bound of the two-sided 95% confidence interval (CI) greater than 89%." The Vstrip device's performance is then reported against these implied criteria.
| Acceptance Criteria (Implied by Comparator ELISA Performance) | Reported Device Performance (Vstrip® H.pylori Antigen Rapid Test) |
|---|---|
| Positive Percent Agreement (PPA) with comparator ELISA: ≥ 95% (with 95% CI lower bound > 89%) | 96.67% [58/60; 95% CI 88.64% - 99.08%] |
| Negative Percent Agreement (NPA) with comparator ELISA: ≥ 95% (with 95% CI lower bound > 89%) | 98.17% [268/273; 95% CI 95.79% - 99.22%] |
Other performance studies with implied acceptance criteria:
| Study Category | Implied Acceptance Criteria | Reported Device Performance |
|---|---|---|
| Reproducibility | High agreement with expected results across operators and sites. | Across all sites and operators, agreement with the expected result was: |
- Moderate positive: 97.8% (88/90)
- Low positive: 97.8% (88/90)
- High negative: 98.9% (89/90)
- True negative: 100% (90/90) |
| Analytical Sensitivity (LOD) | A defined Limit of Detection (LOD) for the strains tested. | LOD for ATCC 43504: 8.5 x 10^5 CFU/mL
LOD for ATCC 51653: 1.9 x 10^5 CFU/mL |
| Inclusivity | Positive results for additional H. pylori strains. | ATCC700392: 3.8 x 10^5 CFU/mL (positive at least 95% of the time)
ATCC 51110: 1.9 x 10^5 CFU/mL (positive at least 95% of the time)
BCRC 17132: 3.8 x 10^6 CFU/mL (positive at least 95% of the time) |
| Analytical Specificity (Cross-reactivity) | No false positive or false negative results with non-target microorganisms. | None of the microorganisms tested produced false positive or false negative results. (Tested 37 bacteria, 7 virus types) |
| Interfering Substances | No interference with assay results from common medications or endogenous substances. | None of the substances with the indicated concentrations interfered with the performance. (Tested 15 potentially interfering substances) |
| Sample Stability | Established stability parameters for storage and freeze/thaw cycles. | Stool samples can be stored: - Up to 7 days refrigerated at 2-8°C
- Up to 20 days frozen at -20°C
Samples can undergo up to three freeze/thaw cycles. |
| Dose-Hook Effect (Prozone) | No negative affects on performance at high antigen concentrations. | No dose hook effect was observed at the tested concentrations (10^5 - 10^8 CFU/mL, 10-100X LoD for 5 H. pylori strains). |
2. Sample Size Used for the Test Set and Data Provenance
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Sample Size for Comparison Study (Test Set): A total of 333 fresh fecal specimens.
- Provenanc_e: 150 fresh fecal samples collected in the USA and 183 fresh fecal samples collected in Taiwan. The study was prospective as samples were collected for the study from the intended use population.
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Sample Size for Reproducibility Study: 5 panels of 12 frozen fecal samples each, analyzed over 5 days by multiple operators at multiple laboratories. This means 5 panels * 12 samples/panel * 5 days = 300 samples per operator for the agreement calculation, and 90 replicates per panel member (5 panels * 18 replicates/panel, with 3 sites * 2 operators * 3 replicates). The specific breakdown for 90 replicates is 3 sites * 2 operators * 5 days * 3 replicates, suggesting a total of 90 replicates per panel member.
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Sample Size for Analytical Sensitivity (LOD): Each dilution was tested 10 times by four operators (a total of 40 replicates).
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Sample Size for Inclusivity: Not explicitly stated, but implies sufficient testing to achieve 95% positive results.
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Sample Size for Analytical Specificity: Each condition was run in triplicate. (37 bacteria and 7 virus types).
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Sample Size for Interfering Substances: Both positive and negative samples tested in triplicate for each of the 15 substances.
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Sample Size for Dose-Hook Effect Study: Five H. pylori strains were tested in triplicate at various concentrations.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Their Qualifications
The ground truth for the comparison study was established by an FDA cleared H. pylori stool antigen ELISA that had been previously evaluated relative to an endoscopy biopsy composite reference method. Therefore, no human experts were involved in establishing the ground truth for this device's test set directly. The ground truth for the comparator ELISA itself was established via a composite reference method (culture, histology, and RUT), which would typically involve expert interpretation (e.g., pathologists for histology, microbiologists for culture/RUT), but the focus of this 510(k) is the Vstrip device's performance against the cleared ELISA, not the ELISA's performance against the composite reference.
4. Adjudication Method for the Test Set
Since the ground truth for the comparison study was established by a single, previously validated ELISA, there was no adjudication method described for the Vstrip device's test set. The Vstrip results were simply compared to the ELISA results.
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
No MRMC comparative effectiveness study was done. This device is a rapid diagnostic test (qualitative immunoassay) and is not intended to be "read" by human readers in the same way an imaging AI study is. The result (presence/absence of line) is a direct output of the device, not an interpretation of a complex image. Therefore, there's no concept of human readers improving with AI assistance in this context.
6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) was done
This device is essentially a standalone test in its performance evaluation. The "reading" of the test (presence of lines) is visual and straightforward, not involving a complex "human-in-the-loop" interpretation process like an imaging algorithm. The "reported device performance" directly reflects the algorithm's (immunoassay's) output. The comparison study evaluates the device's agreement with a reference method, which is a standalone performance assessment.
7. The Type of Ground Truth Used
The primary ground truth for the device's performance evaluation was an FDA cleared H. pylori stool antigen ELISA. This ELISA, in turn, had its ground truth established previously by a composite reference method (culture, histology, and RUT). So, indirectly, the ground truth traces back to a combination of laboratory and pathology results.
8. The Sample Size for the Training Set
The provided text does not mention a training set or machine learning model. The Vstrip H.pylori Antigen Rapid Test is an immunochromatographic assay, a biochemistry-based diagnostic test, not an AI or machine learning algorithm. Therefore, the concept of a "training set" in the context of machine learning doesn't apply. The development of such a device involves biochemical optimization rather than data-driven model training.
9. How the Ground Truth for the Training Set was Established
As there is no training set for this type of device (immunoassay), this question is not applicable. The development of the device likely involved extensive research and development to select appropriate antibodies and optimize the assay chemistry to achieve specificity and sensitivity to H. pylori antigens.
§ 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).