The BD Directigen™ EZ Flu A+B test is a rapid chromatographic immunoassay for the direct and qualitative detection of influenza A and B viral antigens from nasopharyngeal washes/aspirates, nasopharyngeal swabs and throat swabs of symptomatic patients. The Directigen™ EZ Flu A+B test is a differentiated test, such that influenza A viral antigens can be distinguished from influenza B viral antigens from a single processed sample using a single device. The test is to be used as an aid in the diagnosis of influenza A and B viral infections. All negative test results should be confirmed by cell culture because negative results do not preclude influenza virus infection and should not be used as the sole basis for treatment or other management decisions.

Device Description

The Directigen EZ Flu A+B test is a chromatographic assay to qualitatively detect influenza A and B viral antigens in samples processed from respiratory specimens. When specimens are processed and added to the test device, influenza A or B viral antigens bind to anti-influenza antibodies conjugated to visualizing particles in the corresponding A and B test strips. The antigen-conjugate complex migrates across the test strip to the reaction area and is captured by the line of antibody on the membrane. to other result for influenza A is visualized as a reddish purple line at the Test "T" position and the Control "C" position in the Directigen EZ Flu A read window. A positive result for influenza B is visualized as a reddish purple line at the Test "T" position and the Control "C" position in the Directigen EZ Flu B read window.

AI/ML Overview

Here's an analysis of the provided text regarding the BD Directigen™ EZ Flu A+B test:

1. Table of Acceptance Criteria and Reported Device Performance

Acceptance Criteria (Stated or Implied)	Reported Device Performance
Limit of Detection (LOD) for A/California/4/2009 (H1N1)	3.5 Log10 TCID50/mL, equivalent to 5.37 x 10^2 TCID50/mL
Limit of Detection (LOD) for A/California/7/2009 (H1N1)	3.5 Log10 TCID50/mL, equivalent to 1.86 x 10^3 TCID50/mL
Qualitative detection of influenza A and B viral antigens	The device showed reactivity with cultured strains of A/California/4/09 and A/California/7/09. (The document focuses on LOD for new strains, assuming general qualitative detection for previously cleared strains via substantial equivalence). A disclaimer was added: "although this test has been shown to detect the 2009 H1N1 virus cultured from a positive human respiratory specimen, the performance characteristics of this device with clinical specimens that are positive for the 2009 H1N1 influenza virus have not been established."
Ability to distinguish between influenza A and B viral antigens	The device differentiates influenza A from B (stated in Intended Use and Product Description). The study presented does not re-evaluate this specific differentiation; it focuses on H1N1 strain detection.
Substantial equivalence to predicate device (BD Directigen™ EZ Flu A+B)	The FDA determined the device is substantially equivalent to the predicate device. The additions made to the labeling (new strain data) did not change the intended use or fundamental scientific technology.

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

Sample Size:
- For A/California/4/2009: Undiluted virus culture tested in triplicate. 10-fold dilutions tested in singlicate. Half-log dilutions prepared around the last positive 10-fold dilution and tested in triplicate.
- For A/California/7/2009: Undiluted virus culture tested in triplicate. 10-fold dilutions tested in singlicate. Half-log dilutions prepared around the last positive 10-fold dilution and tested in triplicate.
- Note: The sample size here refers to the number of test runs/replicates per dilution, not patient samples, as this was an analytical sensitivity study using cultured viruses.
Data Provenance: The study was conducted at the Department of Microbiology, University of Hong Kong. The viruses (A/California/4/2009 and A/California/7/2009) were provided by the WHO Collaborating Centre for Surveillance, Epidemiology and Control of Influenza, US Centres for Disease Control and Prevention via the WHO Influenza Collaborating Centre, St Jude Children's Research Hospital, Memphis TN. This is an analytical study using cultured viral strains, not clinical patient data. The provenance is therefore lab-based, international collaboration.

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

Number of Experts: Not directly specified for establishing the actual ground truth of the viral concentration (TCID50 titre).
Qualifications of Experts: Professor JSM Peiris and Dr KH Chan at the Department of Microbiology, University of Hong Kong conducted the study. The identity of the cultured viruses was confirmed using the CDC Swine Influenza Virus Real-time RT-PCR Protocol and reagents supplied by the US CDC. Quantitative virus culture (TCID50) was determined according to the Reed and Muench Method. The test results were read by two independent operators. Their specific qualifications beyond "independent operators" are not detailed in this document.

4. Adjudication Method for the Test Set

The test results were read by two independent operators. The document does not specify an explicit adjudication method (e.g., 2+1, 3+1) if their readings disagreed. It simply states they were read by two independent operators.

5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done, If So, What Was the Effect Size of How Much Human Readers Improve With AI vs Without AI Assistance

No, an MRMC comparative effectiveness study was not done. This submission is for a rapid immunoassay device (a diagnostic test kit), not an AI-based system that assists human readers.

6. If a Standalone (i.e. algorithm only without human-in-the loop performance) Was Done

Yes, a standalone study was done. This was an analytical sensitivity study of the device itself (the kit) using cultured viral strains, essentially evaluating the device's inherent ability to detect target analytes. While human operators are involved in running the test and reading results, the performance being assessed is that of the assay kit in detecting the virus at certain concentrations.

7. The Type of Ground Truth Used

Quantitative Virus Culture: The ground truth for the test set was established by determining the Tissue Culture Infectious Dose (TCID50) according to the Reed and Muench Method. This method quantifies the concentration of infectious virus in a sample, which serves as the gold standard for defining the amount of virus present at each dilution. The identity of the viruses was further confirmed using CDC's RT-PCR protocol.

8. The Sample Size for the Training Set

The document describes an analytical study for new strain reactivity and Limit of Detection (LOD) for an already cleared device. There is no explicit "training set" mentioned in the context of this specific 510(k) submission, as it's not a machine learning/AI device. The device itself was likely developed and validated with various strains and specimens initially, but this specific submission focuses on demonstrating reactivity to newly emerging strains.

9. How the Ground Truth for the Training Set Was Established

As there is no explicit "training set" for the purpose of this analytical sensitivity study (which isn't an AI an algorithm), this question is not applicable in the context of the provided document. The device's original development and previous 510(k) submissions would have involved extensive validation with established ground truth methods.

Summary

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K101461
PAGE 1 OF 3

510(K) SUMMARY

JUN 2 4 2010 BECTON, DICKINSON AND COMPANY SUBMITTED BY: 11085 NORTH TORREY PINES ROAD SUITE 210 LA JOLLA, CA 92037 Tel: (858) 795 7890 Fax: (858 795 7885 Gregory P. Payne, RAC, Director Regulatory Affairs CONTACT NAME:

June 15, 2010 DATE PREPARED:

BD Directigen™ EZ Flu A+B test DEVICE TRADE NAME:

Influenza virus serological reagents DEVICE COMMON NAME:

21 CFR 866.3330 DEVICE CLASSIFICATION:

BD Directigen™ EZ Flu A+B test (K063689), PREDICATE DEVICES : (K042472)

INTENDED USE :

Performance characteristics for Influenza B using nasopharyngeal swabs (NPS) were established primarily with retrospective, frozen specimens. Users may wish to establish the sensitivity of this test for Influenza B using fresh nasopharyngeal swab specimens.

DEVICE DESCRIPTION :

PAGE 2 OF3

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result for influenza B is visualized as a reddish purple line at the Test "T" position and the Control "C" position in the Directigen EZ Flu B read window.

DEVICE COMPARISON:

The modified device differs from the currently marketed BD Directigen™ EZ Flu A+ B test in the following ways:

The labeling has been changed to reflect the addition of analytical sensitivity (LOD) data for A/California/4/2009 and A/California/7/2009 and the Strain Reactivity tables were updated accordingly.

In addition, instructions for the use of controls were modified to reflect the use of dry swab controls. The modification of the control material was under review at the same time as this submission and the modification has been cleared under K101529.

Modifications to the labeling are as follows:

Modification	Potential Impact of Change
1. Addition of data for analytical sensitivity and update tothe strain reactivity tables for A/California/04/2009 andA/California/07/2009.	No impact to the assay kit because of addition of newdata on LOD.
A disclaimer was added: "although this test has beenshown to detect the 2009 H1N1 virus cultured from apositive human respiratory specimen, the performancecharacteristics of this device with clinical specimens thatare positive for the 2009 H1N1 influenza virus have notbeen established. The BD Directigen EZ Flu A+B testcan distinguish between influenza A and B viruses, but itcannot differentiate influenza subtypes."
2. Labeling was changed to reflect a change of controlfrom liquid to dry swab. Instructions for the use ofcontrols were modified to reflect the use of dry swabcontrols. (K101529)	This modification was done under K101529.Verifcation and validation studies were conductedaccording to Design Control procedures to substantiatethe modification of controls from liquid to dry swab.There was no impact on the assay.

SUMMARY OF THE STUDIES

This study was conducted by Professor JSM Peiris and Dr KH Chan at the Department of Microbiology, University of Hong Kong. A/California/4/2009 and A/California/7/2009 viruses were provided by the WHO Collaborating Centre for Surveillance, Epidemiology and Control of Influenza, US Centres for Disease Control and Prevention via the WHO Influenza Collaborating Centre, St Jude Children's Research Hospital, Memphis TN.

The identity of the cultured A/California/4/2009 and A/California/7/2009 viruses was confirmed using the CDC Swine Influenza Virus Real-time RTPCR Protocol for

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Detection and Characterization of Swine Influenza and reagents supplied by the US CDC. Quantitative virus culture was done using MDCK cells grown on microtitre plates.

The Tissue Culture Infectious Dose (TCIDso) was determined according to the Reed and Muench Method.

The study was carried out using test-kits supplied by BD (Lot Number 9310845) according to the protocol supplied by the manufacturer. Undiluted virus culture of each virus was tested in triplicate using the BD Directigen EZ Flu A+B test. Then 10 fold dilutions of each virus were tested in singlicate. Half-log dilutions were prepared around the last dilution to be positive in the singlicate 10-fold dilution series and the test was repeated in triplicate. The test results were read by two independent operators.

The limit of detection of the BD Directigen EZ Flu A+B test on a pandemic H1N1 virus A/California/4/2009 infected MDCK cell culture with a TCID50 titre of 6.23 Log 10 / mL was 3.5 Log10 and for A/California/7/2009 infected MDCK culture with a TC/D66 titre of 6.77 Log 10 / mL was 3.5 Log 10. Therefore, the limit of detection, expressed in TCID50mL, is 5.37X102 for A/California/4/2009 and 1.86X103 for A/California/7/2009.

SUBSTANTIAL EQUIVALENCE:

The modified device BD Directigen™ EZ Flu A+ B test is substantially equivalent to the current legally marketed device. BD Directigen™ EZ Flu A+B test. Additions made to the labeling to add additional strain testing did not change the intended use of the device or the fundamental scientific technology.

Risk analysis was not conducted to add this analytical sensitivity information to the product insert as no new issues of safety and effectiveness were identified for this addition to the product insert.

CONCLUSION

The results from this study indicate that the BD Directigen EZ Flu A+B test shows reactivity with cultured strains of A/California/4/09 and A/California/7/09 (2009 H1N1 influenza virus). The limit of detection (LOD) was demonstrated to be 5.37X102 TCIDsolmL for A/California/4/09 strain and 1.86 X103 TCID50/mL for A/California/7/09 strain. Although this test has been shown to detect the 2009 H1N1 virus cultured from positive human respiratory specimens, the performance characteristics of this device with clinical specimens that are positive for the 2009 H1N1 influenza virus have not been established. The package insert for the device was revised to reflect the additional information.

The modified device BD Directigen™ EZ Flu A+ B test is substantially equivalent to the current legally marketed device, BD Directigen™ EZ Flu A+B test.

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Image /page/3/Picture/1 description: The image is a circular logo for the Department of Health & Human Services USA. The logo features the department's emblem, which is a stylized representation of an eagle or bird with three curved lines forming its body and wings. The emblem is positioned in the center of the circle. Encircling the emblem are the words "DEPARTMENT OF HEALTH & HUMAN SERVICES USA," arranged in a circular fashion around the edge of the logo.

Food and Drug Administration 10903 New Hampshire Avenue Document Mail Center - WO66-0609 Silver Spring, MD 20993-0002

JUN 2 : 20:00

Gregory P. Payne, RAC Director, Regulatory Affairs and Quality Systems BD Diagnostics Becton, Dickinson and Company 11085 North Torrey Pines Road Suite 210 La Jolla, CA 92037

Re: K101461

Trade/Device Name: BD Directigen™ EZ Flu A+B Test Regulation Number: 21 CFR 866.3330 Regulation Name: Influenza Virus Serological Reagents Regulatory Class: Class I Product Code: GNX Dated: May 24, 2010 Received: May 26, 2010

Dear Mr. Payne:

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 (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. 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.

If your device is classified (see above) into class II (Special Controls), it may be subject to such additional controls. Existing major regulations affecting your device can be found in Title 21, Code of Federal Regulations (CFR), Parts 800 to 895. In addition, FDA may publish further announcements concerning your device in the Federal Register.

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 Parts 801 and 809); medical device reporting (reporting of medical device-related adverse events) (21 CFR 803); and good manufacturing practice

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requirements as set forth in the quality systems (QS) regulation (21 CFR Part 820). This letter will allow you to begin marketing your device as described in your Section 510(k) premarket notification. The FDA finding of substantial equivalence of your device to a legally marketed predicate device results in a classification for your device and thus, permits your device to proceed to the market.

If you desire specific advice for your device on our labeling regulation (21 CFR Parts 801 and 809), please contact the Office of In Vitro Diagnostic Device Evaluation and Safety at (301) 796-5450. Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21 CFR Part 807.97). For questions regarding the reporting of adverse events under the MDR regulation (21 CFR Part 803), please go to

http://www.fda.gov/MedicalDevices/Safety/ReportaProblem/default.htm for the CDRH's Office of Surveillance and Biometrics/Division of Postmarket Surveillance.

You may obtain other general information on your responsibilities under the Act from the Division of Small Manufacturers, International and Consumer Assistance at its toll-free number (800) 638-2041 or (301) 796-7100 or at its Internet address http://www.fda.gov/cdrh/industry/support/index.html.

Sincerely yours,

Ilue Schf for

Sally A. Hojvat, M.Sc., Ph.D. Director Division of Microbiology Devices Office of In Vitro Diagnostic Device Evaluation and Safety Center for Devices and Radiological Health

Enclosure

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INDICATION FOR USE

510(K) Number K101461

BD Directigen™ EZ Flu A+B test Device Name:

Indication for Use:

Performance characteristics for Influenza B using nasopharynqeal swabs (NPS) were established primarily with retrospective, frozen specimens. Users may wish to establish the sensitivity of this test for Influenza B using fresh nasopharyngeal swab specimens.

Prescription Use X 21 CFR 801 Subpart D) And/or

Over the Counter Use (21 CFR 801Subpart C)

(PLEASE DO NOT WRITE BELOW THIS LINE; CONTINUE ON ANOTHER PAGE IF NEEDED)

Concurrence of CDRH, Office of In Vitro Diagnostic Device Evaluation and Safety (OIVD)

Uve Schif

Division Sign-Off Office of In Vitro Diagnostic Device Evaluation and Safety

510(k) k 10,461

Regulation Number and Section

§ 866.3328 Influenza virus antigen detection test system.

(a)
Identification. An influenza virus antigen detection test system is a device intended for the qualitative detection of influenza viral antigens directly from clinical specimens in patients with signs and symptoms of respiratory infection. The test aids in the diagnosis of influenza infection and provides epidemiological information on influenza. Due to the propensity of the virus to mutate, new strains emerge over time which may potentially affect the performance of these devices. Because influenza is highly contagious and may lead to an acute respiratory tract infection causing severe illness and even death, the accuracy of these devices has serious public health implications.(b)
Classification. Class II (special controls). The special controls for this device are:(1) The device's sensitivity and specificity performance characteristics or positive percent agreement and negative percent agreement, for each specimen type claimed in the intended use of the device, must meet one of the following two minimum clinical performance criteria:
(i) For devices evaluated as compared to an FDA-cleared nucleic acid based-test or other currently appropriate and FDA accepted comparator method other than correctly performed viral culture method:
(A) The positive percent agreement estimate for the device when testing for influenza A and influenza B must be at the point estimate of at least 80 percent with a lower bound of the 95 percent confidence interval that is greater than or equal to 70 percent.
(B) The negative percent agreement estimate for the device when testing for influenza A and influenza B must be at the point estimate of at least 95 percent with a lower bound of the 95 percent confidence interval that is greater than or equal to 90 percent.
(ii) For devices evaluated as compared to correctly performed viral culture method as the comparator method:
(A) The sensitivity estimate for the device when testing for influenza A must be at the point estimate of at least 90 percent with a lower bound of the 95 percent confidence interval that is greater than or equal to 80 percent. The sensitivity estimate for the device when testing for influenza B must be at the point estimate of at least 80 percent with a lower bound of the 95 percent confidence interval that is greater than or equal to 70 percent.
(B) The specificity estimate for the device when testing for influenza A and influenza B must be at the point estimate of at least 95 percent with a lower bound of the 95 percent confidence interval that is greater than or equal to 90 percent.
(2) When performing testing to demonstrate the device meets the requirements in paragraph (b)(1) of this section, a currently appropriate and FDA accepted comparator method must be used to establish assay performance in clinical studies.
(3) Annual analytical reactivity testing of the device must be performed with contemporary influenza strains. This annual analytical reactivity testing must meet the following criteria:
(i) The appropriate strains to be tested will be identified by FDA in consultation with the Centers for Disease Control and Prevention (CDC) and sourced from CDC or an FDA-designated source. If the annual strains are not available from CDC, FDA will identify an alternative source for obtaining the requisite strains.
(ii) The testing must be conducted according to a standardized protocol considered and determined by FDA to be acceptable and appropriate.
(iii) By July 31 of each calendar year, the results of the last 3 years of annual analytical reactivity testing must be included as part of the device's labeling. If a device has not been on the market long enough for 3 years of annual analytical reactivity testing to have been conducted since the device received marketing authorization from FDA, then the results of every annual analytical reactivity testing since the device received marketing authorization from FDA must be included. The results must be presented as part of the device's labeling in a tabular format, which includes the detailed information for each virus tested as described in the certificate of authentication, either by:
(A) Placing the results directly in the device's § 809.10(b) of this chapter compliant labeling that physically accompanies the device in a separate section of the labeling where the analytical reactivity testing data can be found; or
(B) In the device's label or in other labeling that physically accompanies the device, prominently providing a hyperlink to the manufacturer's public Web site where the analytical reactivity testing data can be found. The manufacturer's home page, as well as the primary part of the manufacturer's Web site that discusses the device, must provide a prominently placed hyperlink to the Web page containing this information and must allow unrestricted viewing access.
(4) If one of the actions listed at section 564(b)(1)(A)-(D) of the Federal Food, Drug, and Cosmetic Act occurs with respect to an influenza viral strain, or if the Secretary of Health and Human Services (HHS) determines, under section 319(a) of the Public Health Service Act, that a disease or disorder presents a public health emergency, or that a public health emergency otherwise exists, with respect to an influenza viral strain:
(i) Within 30 days from the date that FDA notifies manufacturers that characterized viral samples are available for test evaluation, the manufacturer must have testing performed on the device with those viral samples in accordance with a standardized protocol considered and determined by FDA to be acceptable and appropriate. The procedure and location of testing may depend on the nature of the emerging virus.
(ii) Within 60 days from the date that FDA notifies manufacturers that characterized viral samples are available for test evaluation and continuing until 3 years from that date, the results of the influenza emergency analytical reactivity testing, including the detailed information for the virus tested as described in the certificate of authentication, must be included as part of the device's labeling in a tabular format, either by:
(A) Placing the results directly in the device's § 809.10(b) of this chapter compliant labeling that physically accompanies the device in a separate section of the labeling where analytical reactivity testing data can be found, but separate from the annual analytical reactivity testing results; or
(B) In a section of the device's label or in other labeling that physically accompanies the device, prominently providing a hyperlink to the manufacturer's public Web site where the analytical reactivity testing data can be found. The manufacturer's home page, as well as the primary part of the manufacturer's Web site that discusses the device, must provide a prominently placed hyperlink to the Web page containing this information and must allow unrestricted viewing access.