(154 days)
The BD Veritor" System for Rapid Detection of Group A Strep test is a rapid chromatographic immunoassay for the direct and qualitative detection of Group A Streptococcus antigen from throat swabs of symptomatic patients. It is intended to be used in conjunction with the BD Veritor™ System Reader as an aid in the diagnosis of Group A Strep. All negative test results should be confirmed by bacterial culture because negative results do not preclude Group A Strep infection and should not be used as the sole basis for treatment.
The BD Veritor System for rapid detection of Group A Strep test is intended for use in point-of-care or laboratory settings.
The BD Veritor™ System for rapid detection of Group A Strep is a qualitative, lateral flow immunoassay for the detection of Strep A carbohydrate antigen in a throat swab. In this test, antibody specific to Strep A carbohydrate antigen is coated on the test line region of the Assay device. During testing, the processed throat swab specimen reacts with an antibody to Strep A that is conjugated onto detector particles. The mixture migrates up the membrane to react with the antibody to Strep A on the membrane and is captured by the line of antibody on the membrane. A positive result for Strep A is determined by the BD Veritor ™ System Reader when antigen-conjugate is deposited at the Test "T" position and the Control "C" position on the BD Veritor™ System Strep A assay device.
Here's an analysis of the acceptance criteria and study detailed in the provided document for the BD Veritor™ System for Rapid Detection of Group A Strep:
1. Table of Acceptance Criteria and Reported Device Performance
The document does not explicitly state pre-defined acceptance criteria values for sensitivity and specificity. However, based on the Intended Use statement and the comparison to an existing predicate device, we can infer that the device aims for performance comparable to or better than current rapid chromatographic immunoassays for Group A Strep. Given the nature of a 510(k) submission, the "acceptance criteria" here are implicitly met by demonstrating substantial equivalence to the predicate and by achieving clinically acceptable performance metrics.
For the purpose of this response, I will list the observed performance metrics from the clinical study as the "reported device performance." If explicit acceptance criteria were given, they would typically be pre-specified thresholds (e.g., "Sensitivity > 85%", "Specificity > 95%").
| Metric | Reported Device Performance (Overall) |
|---|---|
| Sensitivity | 96.6% (144/149) |
| Specificity | 95.5% (618/647) |
Additional Performance Data (Analytical & Reproducibility):
| Performance Aspect | Details / Reported Performance |
|---|---|
| Analytical Sensitivity (LOD) | - Strain 12384: 1 x 10^5 CFU/mL (95.0% positivity) |
- Strain 19615: 5 x 10^4 CFU/mL (96.7% positivity)
- Strain 25663: 2 x 10^5 CFU/mL (95.0% positivity) |
| Analytical Specificity | - Lancefield Groups A, B, C, D, F, G (at 1x10^9 CFU/mL): Negative results (no cross-reactivity with other Streptococcus groups). - Various bacteria and yeasts (e.g., Arcanobacterium haemolyticum, Candida albicans, E. coli, S. aureus) and viruses (e.g., Adenovirus, Cytomegalovirus, HSV, Influenza): No cross-reactivity observed. |
| Interfering Substances | 40+ common substances found in respiratory samples (e.g., 4-Acetamidophenol, Acetylsalicylic acid, Albuterol, various blood types, nasal sprays, throat lozenges) tested at specified concentrations: None exhibited interference with Group A positive or Group A negative samples. |
| Media Compatibility | Four transport media (Modified Amies, Modified Stuart's, Normal Saline, Phosphate Buffered Saline) and two agar types (Tryptic Soy Agar with 5% Sheep Blood, Selective Strep Agar) were compatible. Expected results were obtained, and acceptance criteria were met for room temperature and overnight frozen storage conditions. |
| Reproducibility | - High negative sample: 1.1% false positive rate (1/90 samples across 3 sites). - Low positive sample: 91.1% positivity (82/90 samples across 3 sites).
- Moderate positive sample: 98.9% positivity (89/90 samples across 3 sites).
- Negative sample: 0% false positive rate (0/90 samples across 3 sites). |
2. Sample Size and Data Provenance (Clinical Study)
- Sample Size for Test Set: 796 prospectively collected specimens.
- Data Provenance: The study was a multi-center clinical trial conducted at one clinical laboratory site and four Point-of-Care (POC) sites. The country of origin is not explicitly stated but is implicitly the USA, given the FDA 510(k) submission. The data was prospective.
- Patient Demographics:
- Gender: 51.8% female, 48.2% male.
- Age: 39.1% = 22 years old.
3. Number of Experts and Qualifications for Ground Truth (Clinical Study)
The document states that the performance was determined by comparison to bacterial culture. This implies that clinical laboratory professionals (e.g., microbiologists, medical technologists) conducted and interpreted the bacterial cultures, which served as the gold standard. The specific number of experts or their years of experience are not explicitly mentioned.
4. Adjudication Method for the Test Set (Clinical Study)
The document does not describe an explicit adjudication method (e.g., "2+1" or "3+1") for discrepancies between the device result and the bacterial culture. The bacterial culture itself is treated as the reference standard. Discrepancies would simply be counted as false positives or false negatives for the device.
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study
- No, an MRMC comparative effectiveness study was not explicitly described in terms of human readers using the device with and without AI assistance.
- The study compares the device's performance (interpreted by the BD Veritor™ System Reader) against bacterial culture, which is a standalone assessment of the device's accuracy. The "Detection Format" section mentions an "opto-electronic reader determines the line intensity... interprets the results using the scoring algorithm, and reports a positive, negative, or invalid result," which indicates an automated interpretation, not a human reader decision with or without AI.
- Therefore, an effect size of how much human readers improve with AI vs. without AI assistance is not applicable/provided in this document.
6. Standalone Performance Study (Algorithm Only)
Yes, a standalone study was done. The entire clinical performance section evaluates the BD Veritor™ System (which includes the device and the associated reader/algorithm for interpretation) as a standalone diagnostic tool. The "opto-electronic reader" described in the device comparison section directly indicates algorithmic interpretation without human intervention for the final positive/negative result.
7. Type of Ground Truth Used (Clinical Study)
The type of ground truth used for the clinical study was bacterial culture (often referred to as the "gold standard" for Group A Strep diagnosis).
8. Sample Size for the Training Set
The document does not specify a separate training set or its sample size for the device's algorithm. It primarily details the clinical validation study (test set). For an IVD device like this, the "training" might involve internal development and optimization using characterized samples, but a dedicated clinical training set of patient samples is not typically reported in the same way as for AI/ML regulatory submissions.
9. How the Ground Truth for the Training Set Was Established
As no specific training set of patient samples is detailed, the method for establishing its ground truth is not provided. If such a set were used during device development, its ground truth would likely also be established through bacterial culture or other highly reliable laboratory methods, similar to the clinical test set.
§ 866.3740
Streptococcus spp. serological reagents.(a)
Identification. Streptococcus spp. serological reagents are devices that consist of antigens and antisera (excluding streptococcal exoenzyme reagents made from enzymes secreted by streptococci) used in serological tests to identifyStreptococcus spp. from cultured isolates derived from clinical specimens. The identification aids in the diagnosis of diseases caused by bacteria belonging to the genusStreptococcus and provides epidemiological information on these diseases. Pathogenic streptococci are associated with infections, such as sore throat, impetigo (an infection characterized by small pustules on the skin), urinary tract infections, rheumatic fever, and kidney disease.(b)
Classification. Class I (general controls). The device is exempt from the premarket notification procedures in subpart E of part 807 of this chapter subject to § 866.9.