The Flowflex Plus COVID-19 + Flu A/B Home Test is a lateral flow immunoassay intended for the qualitative detection and differentiation of SARS-CoV-2, influenza A, and influenza B protein 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 with self-collected anterior nares nasal swab specimens from individuals aged 14 years or older, or with adult-collected anterior nasal swab specimens from individuals two (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 therefore 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.

Device Description

The Flowflex Plus COVID-19 + Flu A/B Home Test is a lateral flow immunoassay.

AI/ML Overview

This FDA 510(k) clearance letter pertains to a lateral flow immunoassay (a type of rapid diagnostic test), not an AI/computer-aided detection (CAD) device. Therefore, many of the requested criteria (like ground truth establishment by experts, adjudication methods, MRMC studies, standalone algorithm performance, and training set information) are not directly applicable or would be established differently for an in-vitro diagnostic (IVD) device.

However, I can extract the relevant information regarding acceptance criteria and performance as presented for this type of device.

Key takeaway for this document: This is a clearance for a physical diagnostic test (Flowflex Plus COVID-19 + Flu A/B Home Test), not a software or AI-based medical device. Therefore, the concepts of "ground truth for test set," "adjudication methods," "MRMC studies," "standalone algorithm performance," and "training set details" are not applicable in the typical AI/CAD sense. Instead, the "ground truth" for an IVD device like this is typically established by a gold standard laboratory method (e.g., PCR), and the performance metrics are sensitivity and specificity against that gold standard.

Here's the breakdown based on the provided document and the nature of the device:

Device: Flowflex Plus COVID-19 + Flu A/B Home Test (Lateral flow immunoassay)

1. Table of Acceptance Criteria and Reported Device Performance:

The document itself does not contain the specific performance data (sensitivity, specificity) or the exact acceptance criteria that were used for clearance. Instead, it is the clearance letter stating that the device has been reviewed and found substantially equivalent. To find the actual performance data and acceptance criteria, one would typically need to refer to the full 510(k) submission summary or associated clinical study reports, which are not included here.

For a lateral flow immunoassay like this, the acceptance criteria would typically be defined as minimum acceptable sensitivity and specificity values for each analyte (SARS-CoV-2, Flu A, Flu B) compared to a gold standard molecular test (e.g., RT-PCR).

Hypothetical Example Table (based on typical IVD clearance expectations, not from this document):

Analyte	Acceptance Criteria (e.g., Minimum Performance)	Reported Device Performance (e.g., Clinical Study Results)
SARS-CoV-2	Sensitivity: ≥ 80% Specificity: ≥ 98%	Data not provided in this clearance letter
Influenza A	Sensitivity: ≥ 85% Specificity: ≥ 95%	Data not provided in this clearance letter
Influenza B	Sensitivity: ≥ 85% Specificity: ≥ 95%	Data not provided in this clearance letter

Study Proving Device Meets Acceptance Criteria:

The document implicitly states that such a study was conducted and reviewed by the FDA, leading to the substantial equivalence determination. This would be a clinical performance study comparing the results of the Flowflex Plus test to a gold standard laboratory test (e.g., RT-PCR).

Details not explicitly in the document, but standard for IVD tests:

2. Sample Size Used for the Test Set and Data Provenance:

Sample Size: Not specified in this clearance letter. For a multi-analyte home test, the sample size would likely be in the hundreds to low thousands of patient samples, ensuring sufficient numbers of positive and negative cases for each analyte.
Data Provenance: Not specified. For home tests, clinical studies typically involve both prospective collection of samples and sometimes the use of banked, de-identified retrospective samples, often from diverse geographical locations to ensure generalizability. It would likely be from symptomatic individuals, mirroring the intended use.

3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of those Experts:

Not applicable in the sense of human image readers for AI. For an in-vitro diagnostic test, the "ground truth" is established by a reference laboratory method, almost always a highly sensitive and specific molecular test (e.g., RT-PCR for SARS-CoV-2 and Influenza). The experts involved would be laboratory professionals performing and interpreting these reference tests, following validated protocols.

4. Adjudication Method for the Test Set:

Not applicable in the sense of imaging adjudication. For IVD tests, if there are discrepancies between the investigational device and the reference method, these are typically investigated by retesting, re-sampling, or sequence analysis, rather than human "adjudication" of a readout in the way one would for an imaging study.

5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study was done:

No, not applicable. MRMC studies are specific to evaluating the impact of AI/CAD on human reader performance, typically in imaging diagnostics. This device is a direct patient-use diagnostic test.

6. If a standalone (i.e., algorithm only without human-in-the-loop performance) was done:

Not applicable. This isn't an algorithm; it's a physical test. The "standalone performance" is simply the test's sensitivity and specificity when read according to its instructions for use, whether by a lay user or healthcare professional.

7. The type of ground truth used:

Molecular Reference Method (e.g., RT-PCR): This would be the gold standard for confirming the presence or absence of SARS-CoV-2, influenza A, and influenza B in the patient samples.

8. The sample size for the training set:

Not applicable in the AI sense. For an IVD like this, there isn't a "training set" for an algorithm. The "training" or development of the immunoassay involves chemical and biological optimization, not machine learning on a dataset. The validation happens through analytical and clinical studies.

9. How the ground truth for the training set was established:

Not applicable for this type of device.

Summary

FDA 510(k) Clearance Letter - Flowflex Plus COVID-19 and Flu A/B Home Test

Page 1

U.S. Food & Drug Administration
10903 New Hampshire Avenue
Silver Spring, MD 20993
www.fda.gov

Doc ID # 04017.07.05

May 10, 2025

ACON Laboratories, Inc.
℅ James Mullally
Vice President, In-Vitro Diagnostic Regulatory Affairs
Mcra
803 7th street NW
Washington, District of Columbia 20001

Re: K250377
Trade/Device Name: Flowflex Plus COVID-19 and Flu A/B 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: February 6, 2025
Received: February 10, 2025

Dear James Mullally:

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.

FDA U.S. FOOD & DRUG ADMINISTRATION

May 10, 2025

ACON Laboratories, Inc.
℅ James Mullally
Vice President, In-Vitro Diagnostic Regulatory Affairs
Mcra
803 7th street NW
Washington, District of Columbia 20001

Dear James Mullally:

U.S. Food & Drug Administration
10903 New Hampshire Avenue
Silver Spring, MD 20993
www.fda.gov

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K250377 - James Mullally Page 2

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" (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-

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K250377 - James Mullally Page 3

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).

Sincerely,

Silke Schlottmann -S
Digitally signed by Silke Schlottmann -S
Date: 2025.05.10 00:40:42 -04'00'

Silke Schlottmann
Deputy Assistant Director
Bacteriology Respiratory and Medical Countermeasures Branch
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)
K250377

Device Name
Flowflex Plus COVID-19 + Flu A/B Home Test

Indications for Use (Describe)

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.

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:

Department of Health and Human Services
Food and Drug Administration
Office of Chief Information Officer
Paperwork Reduction Act (PRA) Staff
PRAStaff@fda.hhs.gov

"An agency may not conduct or sponsor, and a person is not required to respond to, a collection of information unless it displays a currently valid OMB number."

DEPARTMENT OF HEALTH AND HUMAN SERVICES
Food and Drug Administration

Form Approved: OMB No. 0910-0120
Expiration Date: 07/31/2026
See PRA Statement below.

Indications for Use

510(k) Number (if known)
K250377

Device Name
Flowflex Plus COVID-19 + Flu A/B Home Test

Indications for Use (Describe)

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.

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.

Department of Health and Human Services
Food and Drug Administration
Office of Chief Information Officer
Paperwork Reduction Act (PRA) Staff
PRAStaff@fda.hhs.gov

"An agency may not conduct or sponsor, and a person is not required to respond to, a collection of information unless it displays a currently valid OMB number."

FORM FDA 3881 (8/23) Page 1 of 1 PSC Publishing Services (301) 443-6740 EF

Regulation Number and Section

N/A