(157 days)
The Trinity Biotech Uni-Gold™ Strep A test kit is intended for the rapid, in vitro qualitative detection of group A Streptococcal antigen from human throat swabs. It can also be used as a confirmation test of beta-haemolytic colonies obtained from blood agar plates. The test is intended for professional use in physicians offices as an aid in the rapid diagnosis of group A Streptococcal pharyngitis. The test may also be used in hospital laboratories as an aid in the rapid diagnosis of group A Streptococcal pharyngitis and the confirmation of group A Streptococcus from culture.
The extracted sample flows through an absorbent pad containing anti-Strep A antibody conjugated to colloidal gold which binds group A Streptoccal antigen if present, forming an antigen-antibody complex. As this complex travels along the membrane, it becomes immobilised at the test region, which is impregnated with a rabbit polyclonal anti-Strep A antibody, resulting in the formation of a pink/red line. A pink/red line will also appear in the control region of the test indicating proper functioning of the test. In the absence of group A Streptococcal antigen, a pink/red line will only appear in the control line.
- Acceptance Criteria and Reported Device Performance:
| Metric | Acceptance Criteria (Implied) | Reported Device Performance (Uni-Gold Strep A) |
|---|---|---|
| Accuracy (vs. Routine Culture) | Not explicitly stated, but expected to demonstrate "good agreement" | Overall agreement: 97.0% (486/501) |
| Sensitivity (vs. Routine Culture) | Not explicitly stated, but expected to be high. | Sensitivity: 89.0% (97/109) |
| Specificity (vs. Routine Culture) | Not explicitly stated, but expected to be high. | Specificity: 99.2% (389/392) |
| Concordance (vs. Predicate Device) | Expected to demonstrate "Good agreement." | Positive Concordance: 96.6% (86/89) |
| Negative Concordance: 96.6% (398/412) | ||
| Overall Concordance: 96.6% (484/501) | ||
| Culture Confirmation Sensitivity (vs. Streptococcal latex grouping test) | Not explicitly stated, but expected to be high. | Sensitivity: 96.3% (105/109) initially, then 98.1% (105/107) after resolving mixed cultures. |
| Culture Confirmation Specificity (Identified non-Strep A) | Expected to correctly identify non-Strep A colonies. | 100% (117/117) of negative samples were correctly identified in a separate study. |
| Analytical Sensitivity | Not explicitly stated, but to determine the lowest detection level. | 1 x 10^5 cells per swab |
| Analytical Specificity | Expected to show no cross-reactivity with common throat organisms. | No interference by other organisms (pathological and nonpathological) routinely found in the throat. |
| Relative Sensitivity (vs. Predicate with discordant results resolved against culture) | Expected to be high. | 99.0% (97/98 positive results) |
| Relative Specificity (vs. Predicate with discordant results resolved against culture) | Expected to be high. | 99.3% (400/403 negative results) |
| Relative Overall Agreement (vs. Predicate with discordant results resolved against culture) | Expected to be high. | 99.2% (497/501) |
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Sample Size for Test Set and Data Provenance:
- Accuracy Study (Test Set 1): 501 fresh throat samples. Data provenance is not explicitly stated regarding country of origin, but it is a retrospective or concurrent collection as it was tested "both in the immunoassay and by routine culture."
- Comparison to Predicate Device (Test Set 2): 501 total specimens tested. Data provenance is not explicitly stated.
- Culture Confirmation Study (Test Set 3):
- Initial: 109 samples visually positive for Strep A on blood agar plates.
- Second part (non-Strep A confirmation): 224 samples, of which 117 were identified as non-Strep A.
- Third part (blinded and duplicate testing): 6 samples (2 Group A beta-haemolytic, 4 non-Group A beta-haemolytic).
- All these studies appear to be "test sets" as they are used to evaluate the device's performance directly.
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Number of Experts and Qualifications for Ground Truth of Test Set:
- For the core clinical accuracy and comparison studies, the "routine culture" is considered the ground truth. There is no specific mention of "experts" adjudicating these results, as routine culture itself serves as the reference standard in these diagnostic tests.
- For the Culture Confirmation Study (third part), "2 independent physicians" conducted blinded, duplicate testing. Their qualifications are not further specified beyond "physicians."
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Adjudication Method for Test Set:
- In the primary clinical accuracy study, the Uni-Gold™ Strep A results were compared directly against "routine culture." There isn't an explicit adjudication method described beyond this direct comparison.
- For the comparison between Uni-Gold™ Strep A and the predicate device, discordant results were later "resolved against culture" when calculating relative sensitivity/specificity/agreement. This implies that if the two devices disagreed, a third reference (culture) was used to determine the true positive/negative status for performance calculation. This is a form of an adjudication process, likely a 2+1 type (two devices, one gold standard for resolution).
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Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study:
- No, a multi-reader multi-case (MRMC) comparative effectiveness study was not explicitly done. The device is an immunoassay, not an imaging device that would typically involve human readers interpreting results with or without AI assistance. The studies performed compare the device's performance against a reference standard (culture) and a predicate device.
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Standalone (Algorithm Only) Performance:
- Yes, the performance values presented (sensitivity, specificity, agreement, concordance) are for the Uni-Gold™ Strep A test kit operating as a standalone device, without human-in-the-loop assistance in its core detection mechanism. The human interaction is usually limited to performing the test and reading the results, which is inherent to the use of such a diagnostic kit.
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Type of Ground Truth Used:
- Primary Ground Truth: Routine culture (specifically for Group A Streptococcus). This is a well-established laboratory method for identifying bacterial presence and is considered a high-quality reference standard for infectious disease diagnostics.
- Secondary Ground Truth (for Culture Confirmation): Initial culture results confirmed by "Beta-haemolysis and morphology" and "Streptococcal latex grouping test" for further confirmation.
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Sample Size for Training Set:
- The document does not provide information about a separate "training set" for the Uni-Gold™ Strep A test kit. As an immunoassay (lateral flow assay), it is a biochemical test, not a machine learning algorithm that typically requires a distinct training phase with a dedicated dataset. The device's components and assays are developed and validated during the manufacturing process, rather than "trained" on data.
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How Ground Truth for Training Set Was Established:
- Not applicable, as there is no explicit "training set" in the context of this immunoassay device. The scientific principles and reagents are developed based on known biological interactions and established laboratory methods. Analytical studies (sensitivity, specificity) ensure the components function as intended.
§ 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.