(87 days)
The CareSuperb™ COVID-19/Flu A&B Antigen Combo Home Test is a lateral flow immunochromatographic assay intended for the qualitative detection and differentiation of influenza A and influenza B nucleoprotein antigens and SARS-CoV-2 nucleocapsid antigens directly in anterior nasal swab samples from individuals with signs and symptoms of respiratory tract infection. Symptoms of respiratory infections due to SARS-CoV-2 and influenza can be similar. 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 and should be confirmed with an FDA-cleared molecular assay when determined to be appropriate by a healthcare provider. Negative results do not rule out infection with influenza, SARS-CoV-2, or other pathogens.
Individuals who test negative and experience continued or worsening respiratory symptoms, such as fever, cough, and/or shortness of breath, should seek follow up care from their healthcare provider.
Positive results do not rule out co-infection with other respiratory pathogens and therefore do not substitute for a visit to a healthcare provider for appropriate follow-up.
The CareSuperb™ COVID-19/Flu A&B Antigen Combo Home Test is a lateral flow immunoassay intended for the qualitative detection and differentiation of SARS-CoV-2 nucleocapsid antigen, Influenza A nucleoprotein antigen, and Influenza B nucleoprotein antigen from anterior nasal swab specimens.
The CareSuperb™ COVID-19/Flu A&B Antigen Combo Home Test utilizes an adaptor-based lateral flow assay platform integrating a conjugate wick filter to facilitate sample processing. Each test cassette contains a nitrocellulose membrane with immobilized capture antibodies for SARS-CoV-2, Influenza A, Influenza B, and internal control. Following specimen application to the sample port, viral antigens, if present, bind to labeled detection antibodies embedded in the conjugate wick filter. The resulting immune complexes migrate along the test strip and are captured at the respective test lines (C19 for SARS-CoV-2, A for Influenza A, and B for Influenza B), forming visible colored lines. A visible control line (Cont) confirms proper sample migration and test validity. The absence of a control line invalidates the test result.
Each kit includes a single-use test cassette, assay buffer dropper vial, nasal swab, and Quick Reference Instructions (QRI). Test results are visually interpreted 10 minutes after swab removal.
The provided document describes the CareSuperb™ COVID-19/Flu A&B Antigen Combo Home Test, an over-the-counter lateral flow immunoassay for lay users. The study aimed to demonstrate its substantial equivalence to a predicate device and its performance characteristics for qualitative detection and differentiation of SARS-CoV-2, Influenza A, and Influenza B antigens in anterior nasal swab samples.
Here's an analysis of the acceptance criteria and the study proving the device meets them:
1. Table of Acceptance Criteria and Reported Device Performance
While specific acceptance criteria (i.e., pre-defined thresholds the device must meet for clearance) are not explicitly stated as numbered points in this 510(k) summary, they can be inferred from the reported performance data and common FDA expectations for such devices. The performance data presented serves as the evidence that the device met these implied criteria.
| Performance Characteristic | Implied Acceptance Criteria (e.g., typical FDA expectations) | Reported Device Performance |
|---|---|---|
| Clinical Performance (vs. Molecular Assay) | ||
| SARS-CoV-2 - Positive Percent Agreement (PPA) | High PPA (e.g., >80-90%) | 92.5% (95% CI: 86.4%-96.0%) |
| SARS-CoV-2 - Negative Percent Agreement (NPA) | Very high NPA (e.g., >98%) | 99.6% (95% CI: 99.1%-99.8%) |
| Influenza A - PPA | High PPA (e.g., >80-90%) | 85.6% (95% CI: 77.9%-90.9%) |
| Influenza A - NPA | Very high NPA (e.g., >98%) | 99.0% (95% CI: 98.4%-99.4%) |
| Influenza B - PPA | High PPA (e.g., >80-90%) | 86.0% (95% CI: 72.7%-93.4%) |
| Influenza B - NPA | Very high NPA (e.g., >98%) | 99.7% (95% CI: 99.3%-99.9%) |
| Analytical Performance | ||
| Precision (1x LoD) | ≥95% agreement | 99.2% for SARS-CoV-2, 99.2% for Flu A, 99.7% for Flu B (all at 1x LoD) |
| Precision (3x LoD) | 100% agreement expected at higher concentrations | 100% for all analytes at 3x LoD |
| Limit of Detection (LoD) | Lowest detectable concentration with ≥95% positive agreement | Confirmed LoDs provided for various strains (e.g., SARS-CoV-2 Omicron: 7.50 x 10^0 TCID₅₀/Swab at 100% agreement) |
| Co-spike LoD | ≥95% result agreement in presence of multiple analytes | Met for Panel I and II (e.g., 98% for SARS-CoV-2, 97% for Flu A in Panel I) |
| Inclusivity (Analytical Reactivity) | Demonstrate reactivity with diverse strains | Low reactive concentrations established for a wide range of SARS-CoV-2, Flu A, Flu B strains, with 5/5 replicates positive |
| Competitive Interference | No interference from high concentrations of other analytes | 100% agreement, no competitive interference observed |
| Hook Effect | No false negatives at high antigen concentrations | 100% positive result agreement, no hook effect observed |
| Analytical Sensitivity (WHO Std) | Demonstrate sensitivity using international standard | LoD of 8 IU/Swab with 95% (19/20) agreement |
| Cross-Reactivity/Microbial Interference | No false positives (cross-reactivity) or reduced performance (interference) | No cross-reactivity or microbial interference observed (100% agreement for positive samples, 0% for negative) |
| Endogenous/Exogenous Substances Interference | No false positives or reduced performance | No cross-reactivity or interference observed (all target analytes accurately detected) |
| Biotin Interference | Clearly define impact of biotin; specify concentration for potential interference | False negatives for Influenza A at 3,750 ng/mL and 5,000 ng/mL (Important finding for labeling) |
| Real-time Stability | Support claimed shelf-life | 100% expected results over 15 months, supporting 13-month shelf-life |
| Transportation Stability | Withstand simulated transport conditions | 100% expected results, no false positives/negatives under extreme conditions |
| Usability Study | High percentage of correct performance and interpretation by lay users | >98% correct completion of critical steps, 98.7% observer agreement with user interpretation, >94% found instructions easy/test simple |
| Readability Study | High percentage of correct interpretation from QRI by untrained lay users | 94.8% correct interpretation of mock devices from QRI without assistance |
2. Sample Sizes Used for the Test Set and Data Provenance
- Clinical Performance Test Set (Human Samples): N=1644 total participants.
- Self-collecting: N=1447 (individuals aged 14 or older testing themselves)
- Lay-user/Tester Collection: N=197 (adults testing individuals aged 2-17 years)
- Data Provenance:
- Country of Origin: United States ("13 clinical sites across the U.S.").
- Retrospective/Prospective: The clinical study was prospective, as samples were collected "between November of 2023 and March of 2025" from "symptomatic subjects, suspected of respiratory infection."
- Analytical Performance Test Sets (Contrived/Spiked Samples): Sample sizes vary per study:
- Precision Study 1: 360 results per panel member (negative, 1x LoD positive, 3x LoD positive).
- Precision Study 2: 36 sample replicates/lot (for negative and 0.75x LoD positive samples).
- LoD Confirmation: 20 replicates per LoD concentration.
- Co-spike LoD: 20 replicates per panel (multiple panels tested).
- Inclusivity: 5 replicates per strain (for identifying lowest reactive concentration).
- Competitive Interference: 3 replicates per of 19 sample configurations.
- Hook Effect: 5 replicates per concentration.
- WHO Standard LoD: 20 replicates for confirmation.
- Cross-Reactivity/Microbial Interference: 3 replicates per microorganism (in absence and presence of analytes).
- Endogenous/Exogenous Substances Interference: 3 replicates per substance (in absence and presence of analytes).
- Biotin Interference: 3 replicates per biotin concentration.
- Real-time Stability: 5 replicates per lot at each time point.
- Transportation Stability: 5 replicates per sample type per lot for each condition.
- Usability Study: 1,795 participants.
- Readability Study: 50 participants.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts
-
Clinical Performance (Reference Method - Test Set Ground Truth): The ground truth for the clinical test set was established using FDA-cleared molecular RT-PCR comparator assays for SARS-CoV-2, Influenza A, and Influenza B.
- This implies that the "experts" were the established and validated molecular diagnostic platforms, rather than human expert readers/adjudicators for visual interpretation.
-
Usability/Readability Studies:
- Usability Study: "Observer agreement with user-interpreted results was 98.7%." This suggests trained observers (likely not "experts" in the sense of clinical specialists, but rather study personnel trained in test interpretation as per IFU) established agreement with user results.
- Readability Study: The study focused on whether lay users themselves could interpret results after reading the QRI. Ground truth for the mock devices would be pre-determined by the device manufacturer based on their design.
4. Adjudication Method for the Test Set
- Clinical Performance: No human adjudication method (e.g., 2+1, 3+1) is mentioned for the clinical test set. The direct comparison was made against molecular RT-PCR as the gold standard, which serves as the definitive ground truth for the presence or absence of the viruses. This type of diagnostic test typically relies on a definitive laboratory method for ground truth, not human interpretation consensus.
- Usability/Readability Studies: The usability study mentioned "Observer agreement with user-interpreted results," implying direct comparison between user interpretation and a pre-defined correct interpretation or an observer's interpretation. The readability study involved participants interpreting mock devices based on the QRI, with performance measured against the pre-determined correct interpretation of those mock devices.
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 AI Component: This device (CareSuperb™ COVID-19/Flu A&B Antigen Combo Home Test) is a lateral flow immunoassay for visual interpretation. It is not an AI-powered diagnostic device, nor does it have a human-in-the-loop AI assistance component. Therefore, an MRMC study related to AI assistance was not applicable and not performed.
6. If a Standalone (i.e., Algorithm Only Without Human-in-the-Loop Performance) Was Done
- Not Applicable: As this is a visually interpreted antigen test, there is no "algorithm only" or standalone algorithm performance to evaluate. The device's performance is intrinsically linked to its chemical reactions and subsequent visual interpretation by the user (or observer in studies).
7. The Type of Ground Truth Used
- Clinical Performance Test Set: FDA-cleared molecular RT-PCR comparator assays (molecular ground truth). This is generally considered a highly reliable and objective ground truth for viral detection.
- Analytical Performance Test Sets: Generally contrived samples with known concentrations of viral analytes or microorganisms against negative pooled swab matrix. This allows for precise control of the 'ground truth' concentration and presence/absence.
- Usability/Readability Studies: For readability, it was pre-defined correct interpretations of "mock test devices." For usability, it was observation of correct procedural steps and comparison of user interpretation to trained observer interpretation.
8. The Sample Size for the Training Set
- Not explicitly stated in terms of a "training set" for the device itself. As a lateral flow immunoassay, this device is developed through biochemical design, antigen-antibody interactions, and manufacturing processes, rather than through machine learning models that require distinct training datasets.
- The document describes the analytical studies (LoD, inclusivity, interference, etc.) which inform the device's technical specifications and ensure it's robust. The clinical study and usability/readability studies are typically considered validation/test sets for the final manufactured device.
- If this were an AI/ML device, a specific training set size would be crucial. For this type of IVD, the "training" analogous to an AI model would be the research, development, and optimization of the assay components (antibodies, membrane, buffer, etc.) using various known positive and negative samples in the lab.
9. How the Ground Truth for the Training Set Was Established
- Not applicable in the context of a machine learning training set.
- For the development and optimization of the assay (analogous to training), ground truth would have been established through:
- Using quantified viral stocks (e.g., TCID₅₀/mL, CEID₅₀/mL, FFU/mL, IU/mL) to precisely spike into negative matrix (PNSM) to create known positive and negative samples at various concentrations.
- Employing established laboratory reference methods (e.g., molecular assays) to confirm the presence/absence and concentration of analytes in developmental samples.
- Utilizing characterized clinical samples (if available) with confirmed statuses from gold-standard methods early in development.
FDA 510(k) Clearance Letter - CareSuperb COVID-19/Flu A&B Antigen Combo Home Test
Page 1
U.S. Food & Drug Administration
10903 New Hampshire Avenue
Silver Spring, MD 20993
www.fda.gov
Doc ID # 04017.08.00
August 22, 2025
Access Bio, Inc.
Sung Jang
Senior Manager of Regulatory Affairs
7 Fitzgerald Ave.
Monroe Township, New Jersey 08831
Re: K251604
Trade/Device Name: CareSuperb COVID-19/Flu A&B Antigen Combo Home Test
Regulation Number: 21 CFR 866.3987
Regulation Name: Multi-Analyte Respiratory Virus Antigen Detection Test
Regulatory Class: Class II
Product Code: SCA
Dated: May 26, 2025
Received: May 27, 2025
Dear Sung Jang:
We have reviewed your section 510(k) premarket notification of intent to market the device referenced above and have determined the device is substantially equivalent (for the indications for use stated in the enclosure) to legally marketed predicate devices marketed in interstate commerce prior to May 28, 1976, the enactment date of the Medical Device Amendments, or to devices that have been reclassified in accordance with the provisions of the Federal Food, Drug, and Cosmetic Act (the Act) that do not require approval of a premarket approval application (PMA). You may, therefore, market the device, subject to the general controls provisions of the Act. Although this letter refers to your product as a device, please be aware that some cleared products may instead be combination products. The 510(k) Premarket Notification Database available at https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfpmn/pmn.cfm identifies combination product submissions. The general controls provisions of the Act include requirements for annual registration, listing of devices, good manufacturing practice, labeling, and prohibitions against misbranding and adulteration. Please note: CDRH does not evaluate information related to contract liability warranties. We remind you, however, that device labeling must be truthful and not misleading.
If your device is classified (see above) into either class II (Special Controls) or class III (PMA), it may be subject to additional controls. Existing major regulations affecting your device can be found in the Code of Federal Regulations, Title 21, Parts 800 to 898. In addition, FDA may publish further announcements concerning your device in the Federal Register.
Additional information about changes that may require a new premarket notification are provided in the FDA guidance documents entitled "Deciding When to Submit a 510(k) for a Change to an Existing Device"
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K251604 - Sung Jang Page 2
(https://www.fda.gov/media/99812/download) and "Deciding When to Submit a 510(k) for a Software Change to an Existing Device" (https://www.fda.gov/media/99785/download).
Your device is also subject to, among other requirements, the Quality System (QS) regulation (21 CFR Part 820), which includes, but is not limited to, 21 CFR 820.30, Design controls; 21 CFR 820.90, Nonconforming product; and 21 CFR 820.100, Corrective and preventive action. Please note that regardless of whether a change requires premarket review, the QS regulation requires device manufacturers to review and approve changes to device design and production (21 CFR 820.30 and 21 CFR 820.70) and document changes and approvals in the device master record (21 CFR 820.181).
Please be advised that FDA's issuance of a substantial equivalence determination does not mean that FDA has made a determination that your device complies with other requirements of the Act or any Federal statutes and regulations administered by other Federal agencies. You must comply with all the Act's requirements, including, but not limited to: registration and listing (21 CFR Part 807); labeling (21 CFR Part 801 and Part 809); medical device reporting (reporting of medical device-related adverse events) (21 CFR Part 803) for devices or postmarketing safety reporting (21 CFR Part 4, Subpart B) for combination products (see https://www.fda.gov/combination-products/guidance-regulatory-information/postmarketing-safety-reporting-combination-products); good manufacturing practice requirements as set forth in the quality systems (QS) regulation (21 CFR Part 820) for devices or current good manufacturing practices (21 CFR Part 4, Subpart A) for combination products; and, if applicable, the electronic product radiation control provisions (Sections 531-542 of the Act); 21 CFR Parts 1000-1050.
All medical devices, including Class I and unclassified devices and combination product device constituent parts are required to be in compliance with the final Unique Device Identification System rule ("UDI Rule"). The UDI Rule requires, among other things, that a device bear a unique device identifier (UDI) on its label and package (21 CFR 801.20(a)) unless an exception or alternative applies (21 CFR 801.20(b)) and that the dates on the device label be formatted in accordance with 21 CFR 801.18. The UDI Rule (21 CFR 830.300(a) and 830.320(b)) also requires that certain information be submitted to the Global Unique Device Identification Database (GUDID) (21 CFR Part 830 Subpart E). For additional information on these requirements, please see the UDI System webpage at https://www.fda.gov/medical-devices/device-advice-comprehensive-regulatory-assistance/unique-device-identification-system-udi-system.
Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21 CFR 807.97). For questions regarding the reporting of adverse events under the MDR regulation (21 CFR Part 803), please go to https://www.fda.gov/medical-devices/medical-device-safety/medical-device-reporting-mdr-how-report-medical-device-problems.
For comprehensive regulatory information about medical devices and radiation-emitting products, including information about labeling regulations, please see Device Advice (https://www.fda.gov/medical-devices/device-advice-comprehensive-regulatory-assistance) and CDRH Learn (https://www.fda.gov/training-and-continuing-education/cdrh-learn). Additionally, you may contact the Division of Industry and Consumer Education (DICE) to ask a question about a specific regulatory topic. See the DICE website (https://www.fda.gov/medical-devices/device-advice-comprehensive-regulatory-assistance/contact-us-division-industry-and-consumer-education-dice) for more information or contact DICE by email (DICE@fda.hhs.gov) or phone (1-800-638-2041 or 301-796-7100).
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K251604 - Sung Jang Page 3
Sincerely,
JOSEPH BRIGGS -S
Joseph Briggs, Ph.D.
Deputy Director
Division of Microbiology Devices
OHT7: Office of In Vitro Diagnostics
Office of Product Evaluation and Quality
Center for Devices and Radiological Health
Enclosure
Page 4
FORM FDA 3881 (8/23) Page 1 of 1 PSC Publishing Services (301) 443-6740 EF
DEPARTMENT OF HEALTH AND HUMAN SERVICES
Food and Drug Administration
Indications for Use
Form Approved: OMB No. 0910-0120
Expiration Date: 07/31/2026
See PRA Statement below.
510(k) Number (if known)
K251604
Device Name
CareSuperb COVID-19/Flu A&B Antigen Combo Home Test
Indications for Use (Describe)
The CareSuperb COVID-19/Flu A&B Antigen Combo Home Test is a lateral flow immunochromatographic assay intended for the qualitative detection and differentiation of influenza A and influenza B nucleoprotein antigens and SARS-CoV-2 nucleocapsid antigens directly in anterior nasal swab samples from individuals with signs and symptoms of respiratory tract infection. Symptoms of respiratory infections due to SARS-CoV-2 and influenza can be similar. 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 and should be confirmed with an FDA-cleared molecular assay when determined to be appropriate by a healthcare provider. Negative results do not rule out infection with influenza, SARS-CoV-2, or other pathogens.
Individuals who test negative and experience continued or worsening respiratory symptoms, such as fever, cough, and/or shortness of breath, should seek follow up care from their healthcare provider.
Positive results do not rule out co-infection with other respiratory pathogens and therefore do not substitute for a visit to a healthcare provider for appropriate follow-up.
Type of Use (Select one or both, as applicable)
☐ Prescription Use (Part 21 CFR 801 Subpart D) ☒ Over-The-Counter Use (21 CFR 801 Subpart C)
CONTINUE ON A SEPARATE PAGE IF NEEDED.
This section applies only to requirements of the Paperwork Reduction Act of 1995.
DO NOT SEND YOUR COMPLETED FORM TO THE PRA STAFF EMAIL ADDRESS BELOW.
The burden time for this collection of information is estimated to average 79 hours per response, including the time to review instructions, search existing data sources, gather and maintain the data needed and complete and review the collection of information. Send comments regarding this burden estimate or any other aspect of this information collection, including suggestions for reducing this burden, to:
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Page 5
Access Bio, Inc.
7 Fitzgerald Ave. Monroe Township, NJ 08831 ǁ Tel: (732)-873-4040 ǁ Fax: (732)-873-4043 ǁ info@accessbio.net
510(k) Summary
Date Prepared: August 22, 2025
1. Submitter Information
Submitter: Access Bio, Inc.
7 Fitzgerald Ave.
Monroe Township, NJ 08831
Tel.: +1-732-873-4040
Contact Person: Sung Jang, Senior Manager of Regulatory Affairs
Email: sajang@accessbio.net
2. Device Information
Trade Name: CareSuperb™ COVID-19/Flu A&B Antigen Combo Home Test
Common Name: Multi-analyte respiratory virus antigen detection test
Classification: Class II
Classification Name: Multi-Analyte Respiratory Virus Antigen Detection Test
Product Code: SCA
Regulation Number: 21 CFR 866.3987
3. Legally Marketed Predicate Device
Trade Name: WELLlife COVID-19/Influenza A&B Home Test / WELLlife COVID-19/Influenza A&B Antigen Test
Manufacturer: Wondfo USA Co., Ltd.
510(k) Number: K243256
4. Device Description
The CareSuperb™ COVID-19/Flu A&B Antigen Combo Home Test is a lateral flow immunoassay intended for the qualitative detection and differentiation of SARS-CoV-2 nucleocapsid antigen, Influenza A nucleoprotein antigen, and Influenza B nucleoprotein antigen from anterior nasal swab specimens.
The CareSuperb™ COVID-19/Flu A&B Antigen Combo Home Test utilizes an adaptor-based lateral flow assay platform integrating a conjugate wick filter to facilitate sample processing. Each test cassette contains a nitrocellulose membrane with immobilized capture antibodies for SARS-CoV-2, Influenza A, Influenza B, and internal control. Following specimen application to the sample port, viral antigens, if present, bind to labeled detection antibodies embedded in the conjugate wick filter. The resulting immune complexes migrate along the test strip and are captured at the respective test lines (C19 for SARS-CoV-2, A for Influenza A, and B for Influenza B), forming visible colored lines. A visible control line (Cont) confirms proper sample migration and test validity. The absence of a control line invalidates the test result.
Each kit includes a single-use test cassette, assay buffer dropper vial, nasal swab, and Quick Reference Instructions (QRI). Test results are visually interpreted 10 minutes after swab removal.
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4.1. Indications for Use / Intended Use
The CareSuperb™ COVID-19/Flu A&B Antigen Combo Home Test is a lateral flow immunochromatographic assay intended for the qualitative detection and differentiation of influenza A and influenza B nucleoprotein antigens and SARS-CoV-2 nucleocapsid antigen directly in anterior nasal swab samples from individuals with signs and symptoms of respiratory tract infection. Symptoms of respiratory infections due to SARS-CoV-2 and influenza can be similar. 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 and should be confirmed with an FDA-cleared molecular assay when determined to be appropriate by a healthcare provider. Negative results do not rule out infection with influenza, SARS-CoV-2, or other pathogens.
Individuals who test negative and experience continued or worsening respiratory symptoms, such as fever, cough, and/or shortness of breath, should seek follow up care from their healthcare provider.
Positive results do not rule out co-infection with other respiratory pathogens and therefore do not substitute for a visit to a healthcare provider for appropriate follow-up.
5. Comparison with Predicate Device
The CareSuperb™ COVID-19/Flu A&B Antigen Combo Home Test is substantially equivalent in fundamental technology and principles to the legally marketed predicate device, the Wondfo WELLlife COVID-19/Influenza A&B Home Test / WELLlife COVID-19/Influenza A&B Antigen Test (K243256). The comparison of the predicate and proposed devices is summarized in Table 1.
Table 1. Comparison of Predicate and Proposed Devices with Predicate Device
| Contents | Predicate Device | Proposed Device |
|---|---|---|
| Manufacturer | Wondfo USA Co., Ltd. | Access Bio, Inc. |
| Proprietary Name | WELLlife COVID-19/Influenza A&B Home Test / WELLlife COVID-19/Influenza A&B Antigen Test (K243256) | CareSuperb™ COVID-19/Flu A&B Antigen Combo Home Test |
| Intended Use/ Indications for Use | WELLlife™ COVID-19 / Influenza A&B Home Test: The WELLlife™ COVID-19 / Influenza A&B Home Test is a lateral flow immunochromatographic assay intended for the qualitative detection and differentiation of influenza A, and influenza B nucleoprotein antigens and SARS-CoV2 nucleocapsid antigen directly in anterior nasal swab samples from individuals with signs and symptoms of respiratory tract infection. Symptoms of respiratory infections due to SARS-CoV-2 and influenza can be similar. 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 and should be confirmed with an FDA-cleared molecular assay when determined to be appropriate by a healthcare provider. Negative results do not rule out infection with influenza, SARS-CoV-2 or other pathogens. | The CareSuperb™ COVID-19/Flu A&B Antigen Combo Home Test is a lateral flow immunochromatographic assay intended for the qualitative detection and differentiation of influenza A and influenza B nucleoprotein antigens and SARS-CoV-2 nucleocapsid protein directly in anterior nasal swab samples from individuals with signs and symptoms of respiratory tract infection. Symptoms of respiratory infections due to SARS-CoV-2 and influenza can be similar. 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 and should be confirmed with an FDA-cleared molecular assay when determined to be appropriate by a healthcare provider. Negative results do not rule out infection with influenza, SARS-CoV-2, or other pathogens. |
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| Contents | Predicate Device | Proposed Device |
|---|---|---|
| Intended Use/ Indications for Use | Individuals who test negative and experience continued or worsening respiratory symptoms, such as fever, cough and/or shortness of breath, should seek follow-up care from their healthcare provider. Positive results do not rule out co-infection with other respiratory pathogens, and therefore do not substitute for a visit to a healthcare provider or appropriate follow-up. WELLlife™ COVID-19 / Influenza A&B Antigen Test: The WELLlife™ COVID-19 / Influenza A&B Antigen Test is a lateral flow immunochromatographic assay intended for the qualitative detection and differentiation of influenza A, and influenza B nucleoprotein antigens and SARS-CoV2 nucleocapsid antigen directly in anterior nasal swab samples from individuals with signs and symptoms of respiratory tract infection. Symptoms of respiratory infections due to SARS-CoV-2 and influenza can be similar. This test is for use by individuals aged 14 years or older testing themselves, or adults testing aged 2 years or older. All negative results are presumptive and should be confirmed with an FDA-cleared molecular assay when determined to be appropriate by a healthcare provider. Negative results do not rule out infection with influenza, SARS-CoV-2, or other pathogens. Individuals who test negative and experience continued or worsening respiratory symptoms, such as fever, cough and/or shortness of breath, should seek follow-up care from their healthcare providers. Positive results do not rule out co-infection with other respiratory pathogens. Test results should not be used as the sole basis for treatment or other patient management decisions. | Individuals who test negative and experience continued or worsening respiratory symptoms, such as fever, cough, and/or shortness of breath, should seek follow up care from their healthcare provider. Positive results do not rule out co-infection with other respiratory pathogens and therefore do not substitute for a visit to a healthcare provider for appropriate follow-up. |
| Product Code | SCA | SCA |
| Regulation Number | 21 CFR 866.3987 | 21 CFR 866.3987 |
| Regulatory Class | Class II | Class II |
| Common Name | Multi-Analyte Respiratory Virus Antigen Detection Test | Multi-Analyte Respiratory Virus Antigen Detection Test |
| Test Principle | Lateral flow immunoassay | Lateral flow immunoassay |
| Assay Type | Qualitative | Qualitative |
| Intended Users | Over-the-counter lay users or professional use | Over-the-counter lay users |
| Intended Use Population | Self-testing for symptomatic individuals aged 14 years or older and adults testing individuals aged 2 years and older within 4 days post symptom onset. | Self-testing for symptomatic individuals aged 14 years or older and adults testing individuals aged 2 years and older within 4 days post symptom onset. |
| Assay Target | Influenza A nucleoprotein antigen, Influenza B | Influenza A nucleoprotein antigen, Influenza B |
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| Contents | Predicate Device | Proposed Device |
|---|---|---|
| nucleoprotein antigen and/or SARS-CoV-2 nucleocapsid protein antigens | nucleoprotein antigen and/or SARS-CoV-2 nucleocapsid protein antigens | |
| Specimen Type | Direct anterior nasal swab specimen | Direct anterior nasal swab specimen |
| Result Interpretation | Visually read | Visually read |
| Control | Internal control | Internal control |
| Storage Condition | 2-30°C | 2-30°C |
| Development Time | 10-20 minutes | 10-15 minutes |
| Device Type | Test cartridge (cassette) | Test cartridge (cassette with a sample port) |
6. Test Principle
The CareSuperb™ COVID-19/Flu A&B Antigen Combo Home Test is lateral flow immunochromatographic assays intended for the qualitative detection and differentiation of SARS-CoV-2 nucleocapsid antigen, Influenza A nucleoprotein antigen, and Influenza B nucleoprotein antigen from anterior nasal swab specimens. The tests utilize an adaptor-based lateral flow design featuring a cylindrical conjugate wick filter to enhance sample processing and improve analytical sensitivity. The system enables efficient sample and conjugate interaction and promotes continuous migration of analyte–antibody complexes toward the detection zone.
Following sample collection, the swab is inserted into the sample port, and assay buffer is applied to release viral antigens. The extracted sample migrates through the conjugate wick, where labeled antibodies form immune complexes if target antigens are present. These complexes are captured by specific immobilized antibodies on a nitrocellulose membrane, producing visible colored test lines corresponding to SARS-CoV-2 (C19), Influenza A (A), and Influenza B (B). A visible control line (Cont) indicates proper assay performance. Test results are visually interpreted 10 minutes after swab removal.
7. Performance Data
To establish the performance characteristics of the CareSuperb™ COVID-19/Flu A&B Antigen Combo Home Test to the predicate device, following studies were conducted:
7.1. Analytical Performance
1) Precision
A precision study was evaluated in two different studies conducted at single internal site each using three (3) lots of test kits and two (2) operators.
Study 1 was conducted using test samples prepared at three (3) different concentrations of heat inactivated SARS-CoV-2 B.1.1.529, live Flu A: H1N1pdm09/A/Indiana/02/2020, and live Flu B: Victoria/New Hampshire /01/2021 spiked into pooled negative swab matrix (PNSM) to prepare the following test sample panel members: a negative sample, low positive sample (1x co-spike LoD of each analyte), and moderate positive samples (3x co-spike LoD of each analyte). Samples were blinded and randomized before allotting them to the operators. 50μL of each sample was applied to dry nasal swabs and processed per the IFU of the candidate device. All panel members were tested in triplicate with 3 device lots, each in 2 runs per day for each of 2 operators, and the study was conducted for 10 days (i.e., 1 site x 3 lots x 2 operators x 2 runs per day with 3 replicates each x 10 days). 360 results were obtained for each panel member. All replicates prepared at 1xLoD and 3xLoD, demonstrated above 95% agreement across the operators, lots, days and runs test.
Study 2 was performed using a negative sample without any of the analytes, and low positive samples prepared at the 0.75x LoD for each analyte to demonstrate potential lot variability. Two operators tested the samples above in a randomized and blinded manner each using three different lots in a total of 2 runs/operators and across 3 non-consecutive days (i.e., 3 replicates × 2 runs/day × 3 days × 2 operators = 36 sample replicates/lot). The precision of the test was assessed by
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repeating tests over multiple days, by different users, and across three product lots. A summary of the lot-to-lot precision results is provided in Table 2.
Table 2. Summary of Lot-to-lot Precision Results
| Sample Type | Analyte | # of Positive / # of Replicates | % Positive | 95% CI |
|---|---|---|---|---|
| Lot 1 | Lot 2 | Lot 3 | ||
| Negative | NSM | 0/156 | 0/156 | 0/156 |
| Positive (0.75X LoD) | SARS-CoV-2 | 32/36 | 29/36 | 31/36 |
| Flu A | 32/36 | 31/36 | 33/36 | |
| Flu B | 32/36 | 32/36 | 34/36 | |
| Positive (1X LoD) | SARS-CoV-2 | 120/120 | 120/120 | 117/120 |
| Flu A | 120/120 | 120/120 | 117/120 | |
| Flu B | 120/120 | 120/120 | 119/120 | |
| Positive (3X LoD) | SARS-CoV-2 | 120/120 | 120/120 | 120/120 |
| Flu A | 120/120 | 120/120 | 120/120 | |
| Flu B | 120/120 | 120/120 | 120/120 |
2) Limit of Detection (LoD)
Single Analyte LoD
The sensitivity of the CareSuperb™ COVID-19/Flu A&B Antigen Combo Home Test was established by evaluating different concentrations of 2 strains of inactivated SARS-CoV-2 and multiple strains of live influenza A and influenza B. The viruses were diluted in pooled negative swab matrix (PNSM) to generate virus dilutions for testing. The lowest detectable concentration that generated ≥95% positive detection rate was determined as the LoD through serial dilution and confirmed with repeated testing. The confirmed LoDs for the CareSuperb™ COVID-19/Flu A&B Antigen Combo Home Test are summarized in Table 3.
Table 3. Confirmatory LoDs
| Virus Strain | Stock Strain (Titer Unit/mL) | LoD | Result Agreement (%) |
|---|---|---|---|
| Titer Unit/mL | Titer Unit/Swab | ||
| SARS-CoV-2 | |||
| SARS-Related Coronavirus 2, Isolate USA-WA1/2020 | 7.9 x 10⁵ TCID₅₀/mL | 2.63 x 10² TCID₅₀/mL | 1.32 x 10¹ TCID₅₀/Swab |
| SARS-Related Coronavirus 2, Isolate hCoV-19/USA/GA-EHC-2811C/2021 (Lineage B.1.1.529; Omicron Variant) | 1.5 x 10⁶ TCID₅₀/mL | 1.5 x 10² TCID₅₀/mL | 7.50 x 10⁰ TCID₅₀/Swab |
| Influenza A | |||
| A/Brisbane/59/2007 (H1N1) | 1.6 x 10¹⁰ CEID₅₀/mL | 1.6 x 10⁷ CEID₅₀/mL | 8.00 x 10⁵ CEID₅₀/Swab |
| A/Hawaii/66/2019 (H1N1) pdm09 | 7.4 x 10⁹ CEID₅₀/mL | 7.4 x 10⁶ CEID₅₀/mL | 3.70 x 10⁵ CEID₅₀/Swab |
| A/Indiana/02/2020 (H1N1) pdm09 | 9.7 x 10⁸ CEID₅₀/mL | 9.7 x 10⁵ CEID₅₀/mL | 4.85 x 10⁴ CEID₅₀/Swab |
| A/California/55/2020 (H3N2) | 3.5 x 10⁸ FFU/mL | 1.17 x 10⁵ FFU/mL | 5.83 x 10³ FFU/Swab |
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| Virus Strain | Stock Strain (Titer Unit/mL) | LoD | Result Agreement (%) |
|---|---|---|---|
| Titer Unit/mL | Titer Unit/Swab | ||
| A/Delaware/01/2021 (H3N2) | 3.1 x 10⁷ FFU/mL | 3.1 x 10⁴ FFU/mL | 1.55 x 10³ FFU/Swab |
| Influenza B | |||
| B/New Hampshire/01/2021 (Victoria Lineage) | 1.3 x 10⁶ TCID₅₀/mL | 4.33 x 10² TCID₅₀/mL | 2.17 x 10¹ TCID₅₀/Swab |
| B/Michigan/01/2021 (Victoria Lineage) | 5.7 x 10⁶ TCID₅₀/mL | 1.90 x 10³ TCID₅₀/mL | 9.50 x 10¹ TCID₅₀/Swab |
| B/Oklahoma/10/2018 (NA D197N (Yamagata Lineage) | 7.6 x 10⁷ TCID₅₀/mL | 7.6 x 10⁴ TCID₅₀/mL | 3.80 x 10³ TCID₅₀/Swab |
| B/Indiana/17/2017 (NA I221T) (Yamagata Lineage) | 1.0 x 10⁸ TCID₅₀/mL | 3.33 x 10⁴ TCID₅₀/mL | 1.67 x 10³ TCID₅₀/Swab |
Co-spike LoD
Following the establishment of single-analyte LoDs for the CareSuperb™ COVID-19/Flu A&B Antigen Combo Home Test, co-spike LoD equivalency testing was performed to evaluate the performance in the presence of multiple analytes at low concentrations. Co-spiked samples containing all three target analytes—SARS-CoV-2, Influenza A, and Influenza B—each at their respective single-analyte LoD concentrations was tested in twenty (20) replicates. The co-spiked LoD was confirmed if each analyte yielded at least 95% results agreement, demonstrating co-spike equivalency for all analytes to their respective single-analyte LoDs. The confirmed co-spike LoDs are summarized in Table 4.
Table 4. Confirmed Co-spiked LoDs
| Virus Strain | Single-analyte LoD | # of Positive / # of Replicates | Result Agreement (%) |
|---|---|---|---|
| Titer Unit/mL | Titer Unit/Swab | ||
| Panel I | |||
| SARS-Related Coronavirus 2, Isolate hCoV-19/USA/GA-EHC-2811C/2021, (Lineage B.1.1.529; Omicron Variant | 1.5 x 10² TCID₅₀/mL | 7.50 x 10⁰ TCID₅₀/Swab | 59/60 |
| A/Indiana/02/2020 (H1N1) pdm09 | 9.7 x 10⁵ CEID₅₀/mL | 4.85 x 10⁴ CEID₅₀/Swab | 58/60 |
| B/New Hampshire/01/2021 (Victoria Lineage) | 4.33 x 10² TCID₅₀/mL | 2.17 x 10¹ TCID₅₀/Swab | 59/60 |
| Panel II | |||
| SARS-Related Coronavirus 2, Isolate hCoV-19/USA/GA-EHC-2811C/2021, (Lineage B.1.1.529; Omicron Variant | 1.5 x 10² TCID₅₀/mL | 7.50 x 10⁰ TCID₅₀/Swab | 59/60 |
| A/Hawaii/66/2019 (H1N1) pdm09 | 7.4 x 10⁶ CEID₅₀/mL | 3.70 x 10⁵ CEID₅₀/Swab | 58/60 |
| B/Michigan/01/2021 (Victoria Lineage) | 1.90 x 10³ TCID₅₀/mL | 9.50 x 10¹ TCID₅₀/Swab | 59/60 |
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| Virus Strain | Stock Strain (Titer Unit/mL) | LoD | Result Agreement (%) |
|---|---|---|---|
| Titer Unit/mL | Titer Unit/Swab | ||
| A/Delaware/01/2021 (H3N2) | 3.1 x 10⁷ FFU/mL | 3.1 x 10⁴ FFU/mL | 1.55 x 10³ FFU/Swab |
| B/New Hampshire/01/2021 (Victoria Lineage) | 1.3 x 10⁶ TCID₅₀/mL | 4.33 x 10² TCID₅₀/mL | 2.17 x 10¹ TCID₅₀/Swab |
| B/Michigan/01/2021 (Victoria Lineage) | 5.7 x 10⁶ TCID₅₀/mL | 1.90 x 10³ TCID₅₀/mL | 9.50 x 10¹ TCID₅₀/Swab |
| B/Oklahoma/10/2018 (NA D197N (Yamagata Lineage) | 7.6 x 10⁷ TCID₅₀/mL | 7.6 x 10⁴ TCID₅₀/mL | 3.80 x 10³ TCID₅₀/Swab |
| B/Indiana/17/2017 (NA I221T) (Yamagata Lineage) | 1.0 x 10⁸ TCID₅₀/mL | 3.33 x 10⁴ TCID₅₀/mL | 1.67 x 10³ TCID₅₀/Swab |
Co-spike LoD
Following the establishment of single-analyte LoDs for the CareSuperb™ COVID-19/Flu A&B Antigen Combo Home Test, co-spike LoD equivalency testing was performed to evaluate the performance in the presence of multiple analytes at low concentrations. Co-spiked samples containing all three target analytes—SARS-CoV-2, Influenza A, and Influenza B—each at their respective single-analyte LoD concentrations was tested in twenty (20) replicates. The co-spiked LoD was confirmed if each analyte yielded at least 95% results agreement, demonstrating co-spike equivalency for all analytes to their respective single-analyte LoDs. The confirmed co-spike LoDs are summarized in Table 4.
Table 4. Confirmed Co-spiked LoDs
| Virus Strain | Single-analyte LoD | # of Positive / # of Replicates | Result Agreement (%) |
|---|---|---|---|
| Titer Unit/mL | Titer Unit/Swab | ||
| Panel I | |||
| SARS-Related Coronavirus 2, Isolate hCoV-19/USA/GA-EHC-2811C/2021, (Lineage B.1.1.529; Omicron Variant | 1.5 x 10² TCID₅₀/mL | 7.50 x 10⁰ TCID₅₀/Swab | 59/60 |
| A/Indiana/02/2020 (H1N1) pdm09 | 9.7 x 10⁵ CEID₅₀/mL | 4.85 x 10⁴ CEID₅₀/Swab | 58/60 |
| B/New Hampshire/01/2021 (Victoria Lineage) | 4.33 x 10² TCID₅₀/mL | 2.17 x 10¹ TCID₅₀/Swab | 59/60 |
| Panel II | |||
| SARS-Related Coronavirus 2, Isolate hCoV-19/USA/GA-EHC-2811C/2021, (Lineage B.1.1.529; Omicron Variant | 1.5 x 10² TCID₅₀/mL | 7.50 x 10⁰ TCID₅₀/Swab | 59/60 |
| A/Hawaii/66/2019 (H1N1) pdm09 | 7.4 x 10⁶ CEID₅₀/mL | 3.70 x 10⁵ CEID₅₀/Swab | 58/60 |
| B/Michigan/01/2021 (Victoria Lineage) | 1.90 x 10³ TCID₅₀/mL | 9.50 x 10¹ TCID₅₀/Swab | 59/60 |
3) Inclusivity (Analytical Reactivity)
The analytical reactivity of the CareSuperb™ COVID-19/Flu A&B Antigen Combo Home Test was evaluated using a panel of temporally, geographically, and genetically diverse strains of SARS-CoV-2, Influenza A, and Influenza B. A series of 10-fold dilution was established for each virus strain by spiking the strain into pooled NSM to initially determine the lowest reactive concentration. Following identification of the lowest 10-fold dilution yielding 100% positive results, additional testing was performed using two-fold serial dilutions. The lowest dilution that produced 5/5 positive results was established as the strain-specific detection endpoint and presented in Table 5.
Table 5. Reactivity with SARS-CoV-2, Influenza A and Influenza B Virus Strains
| Virus Strain | Lowest Reactive Concentration (Titer Unit/mL) | # of Positive / # of Replicates |
|---|---|---|
| SARS-CoV-2 | ||
| SARS-Related Coronavirus 2 (SARS-CoV-2) Lineage BA.2.12.1 | 6.30 x 10² TCID₅₀/mL | 5/5 |
| SARS-Related Coronavirus 2 (SARS-CoV-2) Lineage BA.2.3 | 1.17 x 10² TCID₅₀/mL | 5/5 |
| SARS-Related Coronavirus 2 (SARS-CoV-2) Lineage BA.2.75.5 | 8.50 x 10¹ TCID₅₀/mL | 5/5 |
| SARS-Related Coronavirus 2 (SARS-CoV-2) Lineage BA.4.6 | 5.75 x 10² TCID₅₀/mL | 5/5 |
| SARS-Related Coronavirus 2 (SARS-CoV-2) Lineage JN.1.4 | 2.11 x 10² TCID₅₀/mL | 5/5 |
| Influenza A | ||
| A/Wisconsin/588/2019 (H1N1)pdm09 | 1.40 × 10³ FFU/mL | 5/5 |
| A/Dominican Republic/7293/2013 (H1N1)pdm09 | 1.25 × 10³ TCID₅₀/mL | 5/5 |
| A/Massachusetts/15/2013 (H1N1)pdm09 | 8.00 × 10⁵ CEID₅₀/mL | 5/5 |
| A/Bangladesh/3002/2015 (H1N1)pdm09 | 1.3 × 10⁴ CEID₅₀/mL | 5/5 |
| A/Michigan/45/2015 (H1N1)pdm09 | 7.8 × 10² TCID₅₀/mL | 5/5 |
| A/Iowa/53/2015 (H1N1)pdm09 | 1.45 × 10⁶ CEID₅₀/mL | 5/5 |
| A/St. Petersburg/61/2015 (H1N1pdm09) | 4.65 × 10⁵ CEID₅₀/mL | 5/5 |
| A/Hong Kong/H090-761-V1(0)/2009 (H1N1)pdm09 | 4.00 × 10² TCID₅₀/mL | 5/5 |
| A/Victoria/4897/2022 (H1N1)pdm09 | 1.0 × 10⁶·⁵ EID₅₀/mL | 5/5 |
| A/Victoria/2570/2019 (H1N1)pdm09 | 1.0 × 10⁵·³ EID₅₀/mL | 5/5 |
| A/New York/21/2020 (H3N2) | 1.30 × 10⁵ FFU/mL | 5/5 |
| A/Michigan/173/2020 (H3N2) | 1.95 × 10⁵ FFU/mL | 5/5 |
| A/Tasmania/503/2020 (H3N2) | 6.50 × 10⁴ FFU/mL | 5/5 |
| A/Texas/50/2012 (H3N2) | 8.75 × 10³ TCID₅₀/mL | 5/5 |
| A/Switzerland/9715293/2013 (H3N2) | 6.00 × 10⁵ CEID₅₀/mL | 5/5 |
| A/Hong Kong/4801/2014 (H3N2) | 9.6 × 10⁵ CEID₅₀/mL | 5/5 |
| A/Singapore/INFIMH-16-0019/2016 (H3N2) | 5.50 × 10⁴ CEID₅₀/mL | 5/5 |
| A/Perth/16/2009 (H3N2) | 1.1 × 10⁵ CEID₅₀/mL | 5/5 |
| A/Darwin/9/2021 (H3N2) | 1.0 × 10⁴·³ EID₅₀/mL | 5/5 |
| A/Georgia/02/2022 (H3N2) | 5.00 × 10⁵·⁵ EID₅₀/mL | 5/5 |
| A/bovine/Ohio/B24OSU-439/2024 (H5N1) | 3.1 × 10² TCID₅₀/mL | 5/5 |
| Influenza B | ||
| B/Texas/43/2019 (Victoria Lineage) | 5.0 × 10² TCID₅₀/mL | 5/5 |
| B/Washington/02/2019 (Victoria Lineage) | 2.1 × 10⁶ CEID₅₀/mL | 5/5 |
| B/Brisbane/60/2008 (Victoria Lineage) | 5 × 10³ CEID₅₀/mL | 5/5 |
| B/Austria/1359417/2021 (Victoria Lineage) | 5.00 × 10⁴·⁵ EID₅₀/mL | 5/5 |
| B/Netherlands/10894/2022 (Victoria Lineage) | 1.0 × 10⁴·⁷ EID₅₀/mL | 5/5 |
| B/Phuket/3073/2013 (Yamagata Lineage) | 2.75 × 10⁴ CEID₅₀/mL | 5/5 |
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| Virus Strain | Lowest Reactive Concentration (Titer Unit/mL) | # of Positive / # of Replicates |
|---|---|---|
| B/Wisconsin/10/2016 (NA I221V) (Yamagata Lineage) | 3.2 × 10⁵ TCID₅₀/mL | 5/5 |
| B/Texas/06/2011 (Yamagata Lineage) | 1.6 × 10⁵ CEID₅₀/mL | 5/5 |
| B/Phuket/3073/2013 (Yamagata Lineage) | 1.0 × 10³·⁸ EID₅₀/mL | 5/5 |
| B/Norway/2134/2019 (Yamagata Lineage) | 2.5 × 10⁴·⁵ EID₅₀/mL | 5/5 |
4) Competitive Interference
The competitive interference study was conducted to assess whether the presence of a high concentration of one target analyte interferes with the detection of other target analytes in the CareSuperb™ COVID-19/Flu A&B Antigen Combo Home Test. The study evaluated potential cross-analyte inhibition using contrived samples containing various combinations of SARS-CoV-2, Influenza A, and Influenza B at predefined low and high concentrations. Low concentration samples were prepared at 3× the established Limit of Detection (LoD) for each analyte. High concentration samples were prepared at ≥1.0 × 10⁵ TCID₅₀/mL or CEID₅₀/mL, depending on the virus type. A panel of 19 sample configurations was tested in triplicate. All target analytes at low concentrations were detected with 100% agreement, regardless of the presence of high concentrations of other analytes. No evidence of competitive interference was observed in any tested panel. A summary of the panel configurations and corresponding results is presented in Table 6.
Table 6. Sample Panel and Competitive Interference Results
| No. | Target Analyte in Sample (Concentration) | Result Agreement (%) |
|---|---|---|
| SARS-CoV-2 | Influenza A | |
| 1 | - | High |
| 2 | Low | High |
| 3 | Low | High |
| 4 | - | Low |
| 5 | Low | - |
| 6 | Low | Low |
| 7 | High | Low |
| 8 | High | - |
| 9 | High | Low |
| 10 | Low | High |
| 11 | High | High |
| 12 | High | Low |
| 13 | - | High |
| 14 | High | High |
| 15 | High | - |
| 16 | High | High |
| 17 | - | High |
| 18 | - | - |
| 19 | High | - |
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5) Hook Effect Study
A high-dose hook effect study was conducted to determine whether excessive concentrations of SARS-CoV-2, Influenza A, or Influenza B antigens interfere with the detection performance of the CareSuperb™ COVID-19/Flu A&B Antigen Combo Home Test. Each analyte was tested individually across a series of 2-fold serial dilutions using inactivated SARS-CoV-2, live Influenza A, and live Influenza B strains spiked into a pooled NSM. All samples were tested in five replicates and the results yielded 100% positive result agreement with no false negative results indicating no hook effect observed at elevated antigen concentrations. A summary of hook effect study results is provided in Table 7.
Table 7. Summary of Hook Effect Study Results
| Virus Strain | Testing Concentration (Titer Unit/mL) | Result Agreement(%) |
|---|---|---|
| SARS-Related Coronavirus 2, Isolate USA-WA1/2020 | 3.95 x 10⁵ TCID₅₀/mL | 100 |
| SARS-Related Coronavirus 2, Isolate hCoV-19/USA/GA-EHC-2811C/2021 (Lineage B.1.1.529; Omicron Variant) | 7.50 x 10⁵ TCID₅₀/mL | 100 |
| Influenza A, A/Indiana/02/2020 (H1N1) pdm09 | 4.85 x 10⁸ CEID₅₀/mL | 100 |
| Influenza A, A/Delaware/01/2021 (H3N2) | 1.55 x 10⁷ FFU/mL | 100 |
| Influenza B, B/New Hampshire/01/2021 (Victoria Lineage) | 6.50 x 10⁵ TCID₅₀/mL | 100 |
| Influenza B, B/Indiana/17/2017 (NA I221T) (Yamagata lineage) | 5.00 x 10⁷ TCID₅₀/mL | 100 |
6) Analytical Sensitivity (1st WHO International Standard for SARS-CoV-2 Antigen)
The analytical sensitivity of the CareSuperb™ COVID-19/Flu A&B Antigen Combo Home Test was evaluated using the 1st WHO International Standard for SARS-CoV-2 Antigen (NIBSC code: 21/368). To determine the preliminary Limit of Detection (LoD), a 5-fold serial dilution starting from 4000 IU/mL was prepared and tested in triplicate. The preliminary LoD concentration was then confirmed by testing twenty (20) replicates. The final LoD using the WHO standard is presented in Table 8.
Table 8. LoD for 1st WHO International Standard for SARS-CoV-2 Antigen
| SARS-CoV-2 Antigen | LoD | # of Positive / # of Replicates | Result Agreement (%) |
|---|---|---|---|
| IU/mL | IU/Swab | ||
| WHO Standard (NIBSC 21/368) | 160 | 8 | 19/20 |
7) Cross Reactivity/Microbial Interference Study
To evaluate the potential cross-reactivity and microbial interference of the CareSuperb™ COVID-19/Flu A&B Antigen Combo Home Test, 27 microorganisms, including viruses, bacteria, yeast, and representative respiratory flora commonly found in nasal specimens. Each microorganism was tested in triplicate both in the absence and presence of the target analytes—SARS-CoV-2, Influenza A, and Influenza B. Analyte-negative samples were prepared using pooled NSM, while analyte-positive samples were contrived by spiking NSM with all three analytes at 3X the co-spike limit of detection. No cross-reactivity or microbial interference was observed with any of the tested microorganisms. All analyte-negative samples produced negative results, and all analyte-positive samples demonstrated 100% agreement with expected positive results. A summary of the cross reactivity and microbial interference results is provided in Table 9.
Table 9. Summary of Cross-reactivity and Microbial Interference Results
| Microorganism/Virus | Testing Concentration | Cross-Reactivity (Yes/No) | Microbial Interference (Yes/No) |
|---|---|---|---|
| Adenovirus 1 | 1.58 x 10⁵ TCID₅₀/mL | No | No |
| Adenovirus 7 | 1.6 x 10⁵ TCID₅₀/mL | No | No |
| Enterovirus 71, Tainan/4643/1998 | 1.6 x 10⁶ TCID₅₀/mL | No | No |
| Human coronavirus (OC43) | 1.4 x 10⁵ TCID₅₀/mL | No | No |
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| Microorganism/Virus | Testing Concentration | Cross-Reactivity (Yes/No) | Microbial Interference (Yes/No) |
|---|---|---|---|
| Human coronavirus (229E) | 1.4 x 10⁴ TCID₅₀/mL | No | No |
| Human coronavirus (NL63) | 8.0 x 10⁴ TCID₅₀/mL | No | No |
| Human metapneumovirus (hMPV) | 2.8 x 10⁵ TCID₅₀/mL | No | No |
| MERS-Coronavirus, Irradiated Lysate | 1.78 x 10⁵ TCID₅₀/mL | No | No |
| Parainfluenza virus type 1 | 7.4 x 10⁵ TCID₅₀/mL | No | No |
| Parainfluenza virus type 2 | 1.58 x 10⁵ TCID₅₀/mL | No | No |
| Parainfluenza virus type 3 | 1.58 x 10⁵ TCID₅₀/mL | No | No |
| Parainfluenza virus type 4 | 5.0 x 10⁵ TCID₅₀/mL | No | No |
| Respiratory syncytial virus Type B | 1.58 x 10⁵ TCID₅₀/mL | No | No |
| Rhinovirus | 1.58 x 10⁵ TCID₅₀/mL | No | No |
| SARS-Coronavirus | 1.0 x 10⁵ PFU/mL | No | No |
| Human coronavirus HKU1* (clinical specimen) | N/A | No | No |
| Bodetella pertussis | 1.0 x 10⁷ CFU/mL | No | No |
| Chlamydophila pneumoniae | 1.4 x 10⁶ IFU/mL | No | No |
| Haemophilus influenzae | 1.6 x 10⁶ CFU/mL | No | No |
| Legionella pneumophila | 1.35 x 10⁶ CFU/mL | No | No |
| Mycoplasma pneumoniae | 6.5 x 10⁵ CFU/mL | No | No |
| Streptococcus pneumoniae | 1.0 x 10⁷ CFU/mL | No | No |
| Streptococcus pyogenes, Group A | 1.0 x 10⁷ CFU/mL | No | No |
| Staphylococcus aureus | 1.0 x 10⁷ CFU/mL | No | No |
| Staphylococcus epidermidis | 1.0 x 10⁷ CFU/mL | No | No |
| Candida albicans | 1.0 x 10⁷ CFU/mL | No | No |
| Pooled human nasal wash – representative of normal respiratory microbial flora | N/A | No | No |
*10-fold dilution of the stock Human Coronavirus HKU1 (HCoV-HKU1) clinical sample was tested in triplicates in the presence and absence of SARS-CoV-2. The Ct value of the undiluted sample was 11.7.
8) Endogenous and Exogenous Substances Interference Study
The potential interference of endogenous and exogenous substances with the CareSuperb™ COVID-19/Flu A&B Antigen Combo Home Test was evaluated using 43 substances commonly present in respiratory specimens, including over-the-counter (OTC) nasal sprays, throat lozenges, prescription medications, homeopathic remedies, and biological components such as whole blood, buffy coat, mucin, and leukocytes. Each substance was tested in triplicate both in the absence and presence of the target analytes—SARS-CoV-2, Influenza A, and Influenza B—at 3X the established co-spike LoD. Analyte-negative samples were prepared by mixing each substance with pooled NSM, while analyte-positive samples were co-spiked with the target viruses and then mixed with the substances. No cross-reactivity or interference was observed; all target analytes were accurately detected in the presence of the potentially interfering substances, and no false-positive results were observed in their absence. A summary of the endogenous and exogenous substances interference results is provided in Table 10.
Table 10. Summary of Endogenous and Exogenous Substances Interference Results
| Substance | Testing Concentration | Cross-Reactivity (Yes/No) | Interference (Yes/No) |
|---|---|---|---|
| Acetaminophen | 10 mg/mL | No | No |
| Acetyl salicylic acid | 15 mg/mL | No | No |
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| Substance | Testing Concentration | Cross-Reactivity (Yes/No) | Interference (Yes/No) |
|---|---|---|---|
| Beclomethasone | 5 mg/mL | No | No |
| Benzocaine | 5 mg/mL | No | No |
| Budesonide | 2 mg/mL | No | No |
| Chlorpheniramine maleate | 5 mg/mL | No | No |
| Dexamethasone | 1 mg/mL | No | No |
| Dextromethorphan HBr | 2 mg/mL | No | No |
| Diphenhydramine HCl | 5 mg/mL | No | No |
| Flunisolide | 5 mg/mL | No | No |
| Fluticasone | 1 mg/mL | No | No |
| Guaiacol Glyceryl Ether | 20 mg/mL | No | No |
| Histamine Dihydrochloride | 10 mg/mL | No | No |
| Menthol | 10 mg/mL | No | No |
| Mometasone | 1 mg/mL | No | No |
| Molnupiravir | 1 mg/mL | No | No |
| Mucin (Bovine submaxillary glands -Type I-S) | 2.5 mg/mL | No | No |
| Mupirocin | 1 mg/mL | No | No |
| 10 mg/mL | No | No | |
| Phenylpropanolamine | 5 mg/mL | No | No |
| Remdesivir | 1 mg/mL | No | No |
| Tamiflu (Oseltamivir Phosphate) | 5 mg/mL | No | No |
| Tobramycin | 1 mg/mL | No | No |
| Triamcinolone | 1 mg/mL | No | No |
| Zanamivir | 1 mg/mL | No | No |
| Sore Throat Spray (Phenol) | 15 % v/v | No | No |
| Zicam Oral Mist (Zincum aceticum, Zincum gluconicum) | 15 % v/v | No | No |
| Nasal Spray (Phenylephrine HCl) | 15 % v/v | No | No |
| NasalCrom Nasal Spray (Cromloyn sodium) | 15 % v/v | No | No |
| Vicks Sinex Nasal spray (Oxymetazoline HCl) | 15 % v/v | No | No |
| Alkalol Allergy Relief (Galphimia glauca, Luffa operculate, Sabadilla) | 15 % v/v | No | No |
| Zicam Allergy Relief (Galphimia glauca, Histaminum hydrochloricum, Luffa operculate, Sulphur) | 15 % v/v | No | No |
| Hand Sanitizer | 15 % v/v | No | No |
| Hand Soap | 15 % v/v | No | No |
| Whole blood | 2.5 % v/v | No | No |
| Buffy coat | 2.5 % v/v | No | No |
| Allergy Spray (Mometasone Furoate) | 15 % v/v | No | No |
| Budesonide Nasal Spray (Budesonide/Glucocorticoid) | 15 % v/v | No | No |
| Nasacort Allergy 24HR (Triamcinolone acetonide) | 15 % v/v | No | No |
| Allergy Relief Nasal Spray (Fluticasone Propionate) | 15 % v/v | No | No |
| Saline Nasal Spray (Sodium Chloride & Preservatives) | 15 % v/v | No | No |
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| Substance | Testing Concentration | Cross-Reactivity (Yes/No) | Interference (Yes/No) |
|---|---|---|---|
| Alkalol Saline Nasal Spray (Sodium Chloride, Menthol, Thymol, Camphor, Benzoin Resin Extract, Oils of Eucalyptus, Wintergreen, Spearmint, Fir Needle, Cinnamon & Preservatives) | 15 % v/v | No | No |
| Leukocytes | 5.0 x 10⁶ cells/mL | No | No |
| Zinc Throat Spray (Thera Zinc Throat Spray) | 15 % v/v | No | No |
9) Biotin Interference
A biotin interference study was conducted to assess the impact of elevated biotin (vitamin B7) concentrations on test performance. Serial dilutions of biotin (5,000 to 0 ng/mL) were tested in triplicate using both analyte-negative and analyte-positive samples (3X LoD co-spiked SARS-CoV-2, Influenza A, and Influenza B). No false positives were observed at any concentration. However, false negatives were observed for Influenza A at 3,750 ng/mL and 5,000 ng/mL. A summary of biotin interference study is provided in Table 11.
Table 11. Biotin Interference Study Summary
| Biotin Concentration (ng/mL) | # of Positive / # of Replicates |
|---|---|
| SARS-CoV-2 | |
| 5,000 | 3/3 |
| 3,750 | 3/3 |
| 2,500 | 3/3 |
| 1,250 | 3/3 |
| 625 | 3/3 |
| 312.5 | 3/3 |
| 0 | 3/3 |
10) Realtime Stability
A real-time stability study was conducted to evaluate the shelf-life of the CareSuperb™ COVID-19/Flu A&B Antigen Combo Home Test under labeled storage conditions. Three product lots were stored at 2 °C and 30 °C/80% relative humidity, with monthly testing conducted over 15 months. At each time point, five replicates per lot were tested using contrived positive samples spiked with SARS-CoV-2, Influenza A, and Influenza B at 4X the co-spike LoD and confirmed negative samples (natural clinical anterior nasal swab matrix). Across all tested time points and storage conditions, 100% of the replicates yielded expected results with no false positives or false negatives observed. The test kits demonstrated consistent performance supporting a claimed shelf-life of 13 months. The study is ongoing to confirm extended stability and will continue until nonconforming results are observed.
11) Transportation Stability
The transportation stability study evaluated the performance of the CareSuperb™ COVID-19/Flu A&B Antigen Combo Home Test following exposure to simulated extreme shipping conditions. Test kits from three product lots were incubated for ten consecutive days under high-temperature and high-humidity conditions (60°C and 85% relative humidity) to simulate summer transport, and under freezing conditions (–20°C) to simulate winter transport. At each daily interval, test performance was assessed using contrived positive samples containing SARS-CoV-2, Influenza A, and Influenza B antigens at 4X the co-spike LoD and confirmed negative samples prepared using a pooled NSM. Each condition was tested in five replicates per sample type per lot. All results were consistent with expected outcomes and no false positives or false negatives were observed under the tested condition.
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12) Clinical Performance
The clinical performance characteristics of the CareSuperb™ COVID-19/Flu A&B Antigen Combo Home Test was evaluated in symptomatic subjects, suspected of respiratory infection at 13 clinical sites across the U.S. between November of 2023 and March of 2025. Two anterior nasal swab specimens were collected in randomized order from each participant: one swab was self-collected and immediately tested with the CareSuperb™ COVID-19/Flu A&B Antigen Combo Home Test in a simulated home-use setting by participants and the other swab sample was collected by healthcare professional for testing using FDA-cleared molecular RT-PCR comparator assays for SARS-CoV-2, and Influenza A and Influenza B. The CareSuperb™ COVID-19/Flu A&B Antigen Combo Home Test demonstrated the following clinical agreement with the molecular comparator methods.
Table 12. Subject Demographics
| Characteristic | Self-Collecting (N=1447) | Lay-user/ Tester Collection (N=197) | Overall (N=1644) |
|---|---|---|---|
| Age | |||
| Mean (SD) | 42.0 (17.2) | 7.6 (3.7) | 37.8 (19.8) |
| Median [Min, Max] | 41 [13, 90] | 7.5 [2, 17] | 37 [2, 90] |
| Age Group | |||
| 2-13 | 1 | 192 | 193 |
| 14-24 | 267 | 5 | 272 |
| 25-64 | 1025 | 0 | 1025 |
| >64 | 154 | 0 | 154 |
| Sex at Birth | |||
| Female | 842 | 104 | 946 |
| Male | 605 | 93 | 698 |
| Ethnicity | |||
| Hispanic or Latino (of any race) | 635 | 74 | 709 |
| Not Hispanic or Latino | 806 | 116 | 922 |
| Unknown | 6 | 7 | 13 |
| Race | |||
| American Indian or Alaskan Native | 6 | 1 | 7 |
| Asian | 91 | 13 | 104 |
| Black or African American | 208 | 16 | 224 |
| Native Hawaiian or Other Pacific Islander | 14 | 2 | 16 |
| More Than One Race | 31 | 11 | 42 |
| Prefer Not to Answer | 1 | 0 | 1 |
| Unknown | 16 | 12 | 28 |
| White | 1080 | 142 | 1222 |
Table 13. Performance Compared to SARS-CoV-2 Molecular Assay
| CareSuperb™ COVID-19/Flu A&B Antigen Combo Home Test | Comparator | |
|---|---|---|
| Positive | Negative | |
| Positive | 111 | 6 |
| Negative | 9 | 1518 |
| Total | 120 | 1524 |
Positive Percent Agreement (PPA) 92.5% (111/120) (95% CI:86.4%-96.0%)
Negative Percent Agreement (NPA) 99.6% (1518/1524) (95% CI:99.1%-99.8%)
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Table 14. SARS-CoV-2 Performance Stratified by Days Post Symptoms Onset (DPSO)
| DPSO | # of Subject Samples Tested | CareSuperb™ COVID-19/Flu A&B Antigen Combo Home Test Positives | Comparator Positives | PPA |
|---|---|---|---|---|
| Day 0 | 24 | N/A | N/A | N/A |
| Day 1 | 226 | 16 | 18 | 88.9% |
| Day 2 | 567 | 44 | 47 | 93.6% |
| Day 3 | 553 | 35 | 36 | 97.2% |
| Day 4 | 274 | 16 | 19 | 84.2% |
| Total | 1644 | 111 | 120 | 92.5% |
Table 15. Performance Compared to Influenza A Molecular Assay
| CareSuperb™ COVID-19/Flu A&B Antigen Combo Home Test | Comparator | |
|---|---|---|
| Positive | Negative | |
| Positive | 95 | 15 |
| Negative | 16 | 1491 |
| Total | 111 | 1506 |
Positive Percent Agreement (PPA) 85.6% (95/111) (95% CI:77.9%-90.9%)
Negative Percent Agreement (NPA) 99.0% (1491/1506) (95% CI:98.4%-99.4%)
Table 16. Performance Compared to Influenza B Molecular Assay
| CareSuperb™ COVID-19/Flu A&B Antigen Combo Home Test | Comparator | |
|---|---|---|
| Positive | Negative | |
| Positive | 37 | 5 |
| Negative | 6 | 1568 |
| Total | 43 | 1573 |
Positive Percent Agreement (PPA) 86.0% (37/43) (95% CI:72.7%-93.4%)
Negative Percent Agreement (NPA) 99.7% (1568/1573) (95% CI:99.3%-99.9%)
13) Usability Study
A usability study was conducted to evaluate the performance of intended users in conducting the CareSuperb™ COVID-19/Flu A&B Antigen Combo Home Test by assessing the ability of individuals aged 14 and older, as well as adults testing children aged 2 and above, to correctly perform the test and interpret the results in a home setting. Among 1,795 participants representing the lay population, over 98% completed each critical test step correctly, including sample collection, buffer addition, swab handling, timing, and result interpretation. Observer agreement with user-interpreted results was 98.7%. Questionnaire responses indicated that more than 94% of users found the instructions easy to understand and the test simple to perform. The study demonstrated that individuals without training can safely and effectively use the CareSuperb™ COVID-19/Flu A&B Antigen Combo Home Test as intended and the product instruction was found to be clear and accessible across the intended population.
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14) Readability Study
A readability study was conducted to evaluate whether untrained lay users could understand the Quick Reference Instruction (QRI) and correctly interpret test results for the CareSuperb™ COVID-19/Flu A&B Antigen Combo Home Test. Fifty participants aged 14 and older, with diverse educational backgrounds and no medical or laboratory training, were enrolled and asked to interpret ten mock test devices after reading the QRI, without any prior training. The study simulated a home-use environment and included users with and without visual impairments. Out of 500 total device interpretations, 474 (94.8%) were correctly interpreted without assistance. The study concluded that intended users were able to understand the labeling and interpret both positive and negative results accurately.
8. Conclusion
The information provided in this Premarket Notification (510(k)) supports the substantial equivalency of the CareSuperb™ COVID-19/Flu A&B Antigen Combo Home Test to the predicate device, WELLlife™ COVID-19 / Influenza A&B Home Test and WELLlife™ COVID-19 / Influenza A&B Antigen Test in technological and performance characteristics and intended use.
N/A