(212 days)
The CareSuperb™ COVID-19 Antigen Home Test is a visually read lateral flow immunoassay device intended for the rapid, qualitative detection of SARS-CoV-2 virus nucleocapsid protein antigen directly in anterior nasal swab specimens from individuals with signs and symptoms of COVID-19.
This test is for non-prescription home use by individuals aged 14 years or older testing themselves, or adults testing individuals aged 2 years or older.
All negative results are presumptive. Symptomatic individuals with an initial negative test result must be re-tested once between 48 and 72 hours after the first test using either an antigen test or a molecular test for SARS-CoV-2. Negative results do not rule out SARS-CoV-2 infections or other pathogens and should not be used as the sole basis for treatment.
Positive results do not rule out co-infection with other respiratory pathogens.
This test is not a substitute for visits to a healthcare provider or appropriate follow-up and should not be used to determine any treatments without provider supervision. Individuals who test negative and experience continued or worsening COVID-19 symptoms, such as fever, cough and/or shortness of breath, should seek follow up care from their healthcare provider.
Performance characteristics for SARS-CoV-2 were established from October 2023 to April 2024 when SARS-CoV-2 Omicron variant was dominant. Test accuracy may change as new SARS-CoV-2 viruses emerge. Additional testing with a lab-based molecular test (e.g., PCR) should be considered in situations where a new virus or variant is suspected.
The CareSuperb™ COVID-19 Antigen Home Test is a lateral flow immunoassay device intended for the qualitative detection of SARS-CoV-2 nucleocapsid protein in anterior nasal samples.
To begin the test, a self-collected anterior nasal swab sample (in individuals between the age of 2 to 14 a swab collected by a parent or quardian), or a heathcare-provider collected anterior nasal swab sample is inserted into the sample port and the extraction reagent in the dropper vial is added to the extraction to occur exposing the viral nucleocapsid antigens The SARS-CoV-2 antigens present in the sample bind with anti-SARS-CoV-2 antibodies dispensed in the conjuqate wick filter. These antigen-antibody complexes migrate to the the plastic cassette and travel across the membrane through capillary action. The complexes are captured at the tegion, causing a colored line to appear on the membrane.
If the sample contains SARS-CoV-2 antigen, a visible line at the test line ("T") and a procedural control line at the control line ("C") will appear in the result window indicating a positive result. If SARS-CoV 2 viral nucleocapsid antigens are not present, or are present at very low levels, only the procedural control line will appear.
Here's a breakdown of the acceptance criteria and the study that proves the device (CareSuperb™ COVID-19 Antigen Home Test) meets them, based on the provided FDA 510(k) summary:
Summary of Acceptance Criteria and Device Performance
The acceptance criteria for this device are primarily centered around its clinical performance (accuracy) and usability for lay users, as well as robust analytical performance.
1. Table of Acceptance Criteria and Reported Device Performance
| Category | Acceptance Criteria (Implied by FDA Review) | Reported Device Performance |
|---|---|---|
| Clinical Performance | ||
| Positive Percent Agreement (PPA) with RT-PCR (within 4 days of symptom onset) | High agreement (e.g., generally > ~80-90% for antigen tests, with higher expectations for devices for home use) to correctly identify positive samples. | 97.2% (140/144) (95% CI: 93.1%-98.9%) |
| Negative Percent Agreement (NPA) with RT-PCR (within 4 days of symptom onset) | High agreement (e.g., generally > ~95-98% for antigen tests for home use) to correctly identify negative samples. | 98.8% (496/502) (95% CI: 97.4%-99.5%) |
| Analytical Performance | ||
| Precision (Repeatability/Reproducibility) | Consistent results across operators, sample types, lots, and varying concentrations (especially around LoD). | True Negative: 100% agreement (1620/1620). |
| High Negative (0.75X LoD): 92.6% agreement (500/540). | ||
| Low Positive (1X LoD): 99.8% agreement (539/540). | ||
| Low Positive (1.5X LoD, 2X LoD, 4X LoD): 100% agreement. | ||
| Demonstrated precision with no significant variability between lots. | ||
| Limit of Detection (LoD) | Ability to detect SARS-CoV-2 at low concentrations. | WA1/2020: 2.63 x 10^2 TCID50/mL (1.32 x 10^1 TCID50/Swab). |
| Omicron B.1.1.529: 1.5 x 10^2 TCID50/mL (7.5 x 10^1 TCID50/Swab). | ||
| WHO Standard (NIBSC 21/368): 32 IU/mL (1.6 IU/swab). | ||
| Hook Effect | No false negatives at very high concentrations of analyte. | No hook effect observed up to 4.0 x 10^5 TCID50/mL (WA1/2020) and 7.5 x 10^5 TCID50/mL (Omicron B.1.1.529). |
| Cross-Reactivity/Microbial Interference | No false positives or interference from common respiratory microorganisms or viruses. | None of 18 non-SARS-CoV-2 viruses and 10 other microorganisms showed cross-reactivity or interference. Pooled human nasal wash also showed no cross-reactivity or interference. |
| Interfering Substances Effect | No interference from common medications or endogenous substances. | None of 42 tested interfering substances (common medications, endogenous substances like blood, mucin) showed cross-reactivity or interference, except biotin at high concentrations. (False negative results observed when biotin concentration exceeded 2,500 ng/mL in positive samples). This is a known limitation for biotin-sensitive assays. |
| Inclusivity (Analytical Reactivity) | Ability to detect various SARS-CoV-2 variants. | Demonstrated reactivity with 7 additional SARS-CoV-2 variants (Alpha, Delta, Omicron BA.2.12.1, BA.2.3, BA.2.75.5, BA.4.6, JN.1.4) at specific low concentrations. |
| Flex Studies | Robustness to minor variations in user technique and environmental conditions. | Studies support that the test is robust with an insignificant risk of erroneous results under various tested conditions (e.g., reading times, buffer volume, swab handling, environmental stress). |
| Usability & Readability | ||
| Usability Study | Lay users can competently perform critical tasks with the device using provided instructions. | Overall success rate for all critical tasks was ≥ 80% among 50 users. |
| Readability Study | Lay users can correctly interpret test results (positive, negative, invalid). | Overall success rate for both tested panels (negative and positive interpretations) was 95.0% among 50 users. |
2. Sample Size and Data Provenance
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Test Set (Clinical Performance):
- Sample Size: A total of 646 symptomatic subjects were evaluated in the clinical study.
- Data Provenance: Data was collected from 10 clinical sites in the U.S. between October 2023 and April 2024. This was a prospective study, as subjects self-sampled and self-tested in a simulated home setting.
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Analytical Performance Studies: Sample sizes for these studies vary, but are explicitly stated for each (e.g., 540 replicates per lot for precision, 20 replicates for LoD confirmation, 3 replicates for cross-reactivity/interference studies). The document does not specify a country of origin for these lab-based studies, but for a US FDA submission, it implicitly means the studies adhere to US regulatory standards.
3. Number of Experts and Qualifications for Ground Truth
- For the clinical performance study, the ground truth was established by an FDA-cleared molecular assay (RT-PCR). This is a scientific, objective standard, not dependent on human expert interpretation in the same way imaging studies might be.
- For the adjudication of discrepant results in the clinical study, it states: "All discrepant results were investigated by testing using an alternative FDA-cleared molecular assay at the central laboratory." This further reinforces the objective, lab-based ground truth.
- For analytical studies (LoD, cross-reactivity, etc.), ground truth is established by the known concentrations of spiked analytes and the inherent characteristics of the reference materials. These are objective measures rather than expert consensus.
4. Adjudication Method for the Test Set
- For the clinical performance study, the primary ground truth was an FDA-cleared molecular assay.
- Any discrepant results between the CareSuperb™ test and the primary molecular assay were adjudicated by testing with an alternative FDA-cleared molecular assay at a central laboratory. This acts as a robust, independent verification method for discrepancy resolution. There isn't a "2+1" or "3+1" human reader adjudication since the ground truth is objective molecular testing.
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study
- No, an MRMC comparative effectiveness study was not done in the context of human readers improving with AI vs. without AI assistance. This is because the device is a visually read lateral flow immunoassay for COVID-19 antigen detection. It is a standalone diagnostic test performed by lay users, not an AI-assisted interpretation tool for images or complex data that would involve human readers and their performance improvement.
6. Standalone Performance (Algorithm Only)
- Yes, the primary clinical performance data (PPA and NPA) represents the standalone performance of the device when used by lay users, as it is a visually read test. There is no "algorithm" in the sense of a software-based AI interpreting results; the interpretation is visual by the user. The performance metrics (PPA, NPA) directly reflect the device's accuracy in identifying positive and negative cases compared to the molecular reference standard.
7. Type of Ground Truth Used
- Clinical Performance Ground Truth: The primary ground truth for the clinical study was an FDA-cleared molecular assay (RT-PCR) result. Discrepant results were further confirmed by an alternative FDA-cleared molecular assay. This is considered a highly reliable and objective gold standard for SARS-CoV-2 detection.
- Analytical Performance Ground Truth: For the analytical studies (LoD, precision, cross-reactivity, inclusivity), the ground truth was established by using known concentrations of purified or inactivated SARS-CoV-2 strains/variants/reference materials and other microorganisms/substances, diluted into a negative clinical matrix (nasal swab matrix).
8. Sample Size for the Training Set
- The document primarily describes a diagnostic test kit (lateral flow immunoassay), not an AI/ML-based algorithm that requires a "training set" in the computational sense.
- The closest equivalent to a "training set" for physical test development would involve extensive R&D and optimization studies during the design phase to establish reagent concentrations, membrane properties, and other manufacturing parameters. This type of "training" isn't quantified by a sample size of patient data in the same way an AI model's training set would be. The clinical and analytical studies presented are validation studies to prove the device works as intended, not data used for "training" the device itself.
9. How the Ground Truth for the Training Set was Established
- As noted above, there isn't a "training set" and associated ground truth in the AI/ML context for this type of device. The development and optimization of the physical components (e.g., antibody selection, membrane type, buffer formulation) are based on robust analytical chemistry and immunology principles, often using characterized biological materials (like specific viral concentrations) as internal benchmarks during the R&D process. The performance of these optimized components is then validated in the extensive analytical and clinical studies detailed in the 510(k) submission.
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