(97 days)
The Binax NOW® RSV Test is a rapid immunochromatographic assay for the qualitative detection of respiratory syncycial virus (RSV) fusion protein antigen in nasal wash and nasopharyngeal swab specimens from sympromatic patients. This test is intended for in virro diagnostic use to aid in the diagnosis of RSV infections in neonatal and pediatric patients under the age of five. It is recommended that negative test results be confirmed by culture.
The Binax NOW RSV Test is an immunochromatographic membrane assay used to detect RSV antigen in nasopharyngeal specimens. A test scrip, containing gold-conjugated and immobilized and -RSV ancibodies, is mounted on the right side of a cardboard, book-shaped hinged test device. Swab specimens and patients) require a sample preparation seep, in which the sample is eluted off the swab into transport media or saline. Nasal wash samples do not require any preparation. The sample to be tested is added to a pad at the top of the rest strip, and the rest device is closed. RSV antigen present in the sample reacts to bind anti-RSV conjugated antibody. The resulting antigen-conjugate complexes are captured by immobilized anti-RSV antibody, forming the Sample Line Immobilized Control Line antibody, which appears as a blue line in an uncested device, captures a visualizing conjugate, forming a pink Control Line. The sample is contained, and results are available within 15 minutes.
Acceptance Criteria and Device Performance Study for Binax NOW® RSV Test
1. Table of Acceptance Criteria and Reported Device Performance
The provided document does not explicitly state acceptance criteria as numerical targets. Instead, the study aims to establish "substantial equivalence" to a predicate device. The performance is reported in terms of sensitivity and specificity against viral cell culture (or DFA/viral cell culture for nasopharyngeal swabs). We can infer the "acceptance criteria" were implied to be comparable performance to existing methods.
| Test Type | Performance Metric | Reported Performance |
|---|---|---|
| Nasal Wash (Retrospective) | Sensitivity | Not explicitly stated in a tabular format, but implied to be high based on "NOW® test performance versus viral cell culture... was calculated". The accompanying table is unreadable. |
| Specificity | Not explicitly stated. | |
| Nasal Wash (Prospective) | Sensitivity | Not explicitly stated in a tabular format. The accompanying table is unreadable. |
| Specificity | Not explicitly stated. | |
| Nasopharyngeal Swab | Sensitivity | Not explicitly stated in a tabular format. The accompanying table is unreadable. |
| Specificity | Not explicitly stated. | |
| Analytic Reactivity | Detection | Positive for 6 subgroup A and 5 subgroup B clinical isolates of RSV. |
| Analytic Specificity | Cross-reactivity | No cross-reactivity with 48 potential cross-reactants (bacteria and viruses) at specified concentrations, except for Palivizumab. |
| Reproducibility | Correct Interpretation | 100% of 234 samples correctly interpreted across 3 sites. |
2. Sample Sizes and Data Provenance
Nasal Wash - Retrospective Study:
- Sample Size: 59 viral cultured nasal wash specimens.
- Data Provenance: Obtained from a teaching university/medical center in the northeast (USA, presumably). Retrospective.
Nasal Wash - Prospective Study:
- Sample Size: 191 nasal wash specimens.
- Data Provenance: Multi-center, prospective study. Country of origin not specified, but context suggests USA.
Nasopharyngeal Swab - Prospective Study:
- Sample Size: 179 nasopharyngeal swab specimens.
- Data Provenance: Multi-center, prospective study. Country of origin not specified, but context suggests USA.
Reproducibility Study:
- Sample Size: 234 coded specimens (panel containing negative, low positive, and low/moderate positive controls).
- Data Provenance: Blind study conducted at 3 separate sites. Country of origin not specified, but context suggests USA.
3. Number of Experts and Qualifications for Ground Truth
The document does not specify the number or qualifications of experts used to establish the ground truth (viral cell culture or DFA/viral cell culture). It only states that performance was calculated "using standard methods."
4. Adjudication Method for the Test Set
The document does not describe any adjudication method for the test set.
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study
There is no indication that a multi-reader multi-case (MRMC) comparative effectiveness study was done, or any analysis of how human readers improve with AI vs without AI assistance. The device is an immunochromatographic assay, not an AI-powered diagnostic.
6. Standalone (Algorithm Only) Performance
The device is a rapid immunochromatographic assay. The reported clinical sensitivity and specificity studies reflect the standalone performance of the device (algorithm only, as there is no human interpretation component beyond reading the visible lines).
7. Type of Ground Truth Used
- Clinical Studies (Nasal Wash): Viral cell culture.
- Clinical Studies (Nasopharyngeal Swab): DFA/viral cell culture (Direct Fluorescent Antibody / viral cell culture).
8. Sample Size for the Training Set
The document does not specify a separate training set size. The device is a lateral flow immunoassay, not a machine learning algorithm that typically requires a large training dataset in the same way. The development and optimization of the assay would involve internal validation and development studies, but these are not referred to as statistical "training sets" in this context.
9. How the Ground Truth for the Training Set Was Established
Given that this is an immunochromatographic assay and not an AI/machine learning device, the concept of a "training set" with ground truth established in the typical sense for algorithms is not applicable. The development of such a device involves:
- Selection and optimization of antibodies and reagents.
- Establishing critical concentrations and cutoff points through empirical testing with known positive and negative samples (controls, characterized clinical isolates).
- Analytic reactivity and specificity testing (as mentioned in the summary) to ensure proper functioning.
The "ground truth" for these development phases would be based on well-characterized viral isolates, clinical samples confirmed by reference methods (like cell culture), and purified substances.
§ 866.3480 Respiratory syncytial virus serological reagents.
(a)
Identification. Respiratory syncytial virus serological reagents are devices that consist of antigens and antisera used in serological tests to identify antibodies to respiratory syncytial virus in serum. Additionally, some of these reagents consist of respiratory syncytial virus antisera conjugated with a fluorescent dye (immunofluorescent reagents) and used to identify respiratory syncytial viruses from clinical specimens or from tissue culture isolates derived from clinical specimens. The identification aids in the diagnosis of respiratory syncytial virus infections and provides epidemiological information on diseases caused by these viruses. Respiratory syncytial viruses cause a number of respiratory tract infections, including the common cold, pharyngitis, and infantile bronchopneumonia.(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.