The BD ProbeTec™ ET Legionella pneumophila (LP) Amplified DNA Assay, for use with the BD ProbeTec ET System, employs Strand Displacement Amplification (SDA) technology for the direct qualitative detection of Legionella pneumophila DNA (serogroups 1-14) in sputum specimens from patients with a clinical suspicion of pneumonia. It is intended to aid in the presumptive diagnosis of Legionnaires' disease in conjunction with culture and other methods.

Device Description

The BD ProbeTec™ ET LP Amplified DNA Assay is a new test designed for use on the BD ProbeTec™ ET System. The test is indicated for use with sputum specimens from patients with a clinical suspicion of pneumonia as an aid in the presumptive diagnosis of Legionnaires' disease in conjunction with culture and other methods. The BD ProbeTecTM ET LP Amplified DNA Assay is based on the simultaneous amplification and detection of target DNA sequences using nucleic acid primers and fluorescently-labeled detector probes in a process known as strand displacement amplification (SDA). The SDA reagents are dried in two separate disposable microwells. Processed sample containing DNA is added to a Priming Microwell, which contains the amplification primers, fluorescently-labeled detector probes, and other reagents necessary for amplification. Following incubation, the reaction mixture is transferred to an Amplification Microwell, which contains two enzymes (a DNA polymerase and a restriction endonuclease) necessary for SDA. The Amplification Microwells are sealed to prevent contamination and then incubated in a thermally controlled fluorescent reader, which monitors each reaction for the generation of amplified products. Each reaction coamplifies and detects an Internal Amplification Control (IAC), as well as the target DNA. The purpose of the IAC is to verify that proper conditions exist for amplification and to reduce the possibility of reporting a false negative result due to specimen inhibitors. The presence or absence of L. pneumophila DNA is determined by calculating PAT scores (Passes After Threshold) for the specimen based on predefined threshold values. The instrument automatically reports the results as positive, negative or indeterminate.

AI/ML Overview

Here's an analysis of the acceptance criteria and the study that proves the device meets them, based on the provided text:

1. Table of Acceptance Criteria and Reported Device Performance

The document does not explicitly state pre-defined acceptance criteria (e.g., "The device must achieve a sensitivity of at least X%"). Instead, it presents the determined performance metrics from a retrospective study, which presumably were considered acceptable for market clearance given the "Substantial Equivalence" finding. For the purpose of this analysis, I will treat the reported performance as the de facto "met acceptance criteria" based on the FDA's clearance.

Metric	Acceptance Criteria (Implicit)	Reported Device Performance (Retrospective Study)
Sensitivity (Agreement with Culture for Positive Samples)	High agreement expected	91.3% (21/23)
Specificity (Agreement with Culture for Negative Samples)	High agreement expected	86.7% (52/60)
Overall Agreement with Culture	High agreement expected	88% (73/83)

Note on Prospective Study: The prospective study found 100% (114/114) negative agreement with culture, but as there were no culture-positive specimens, sensitivity could not be estimated. This highlights the reliance on the retrospective study for key performance metrics.

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

Prospective Study Test Set:
- Sample Size: 114 sputum specimens from 114 patients.
- Data Provenance: Prospective, collected from seven clinical centers within the United States and Canada during the 2002-2003 respiratory season.
Retrospective Study Test Set (to estimate sensitivity):
- Sample Size: 83 retrospective sputum specimens (23 positive for L. pneumophila by culture, 60 negative by culture).
- Data Provenance: Retrospective, acquired from clinical sites within the United States, Europe, and Canada.

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

The document does not specify the number of experts or their qualifications used to establish the ground truth for the test set.

4. Adjudication Method for the Test Set

The primary ground truth for both the prospective and retrospective studies was bacterial culture.

For the retrospective study, in cases of discordance between the BD ProbeTec™ ET LP Amplified DNA Assay and culture, Polymerase Chain Reaction (PCR) testing was performed on some of the discordant samples for further investigation. This acted as a secondary, confirmatory method, particularly when the culture was positive but the assay negative, or vice-versa. However, PCR was not uniformly applied to all discordant samples (e.g., 6 of 8 culture-negative, assay-positive samples were tested with PCR, and 1 of 2 culture-positive, assay-negative samples was tested with PCR). This suggests a form of partial adjudication.

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, a Multi-Reader Multi-Case (MRMC) comparative effectiveness study was not done. This device is an in-vitro diagnostic (IVD) assay designed for automated detection of DNA, not an AI-assisted imaging tool for human readers. Therefore, the concept of "human readers improve with AI vs without AI assistance" does not apply here.

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

Yes, the performance reported is that of the standalone algorithm. The "BD ProbeTec™ ET LP Amplified DNA Assay" (which uses Strand Displacement Amplification - SDA) is an automated system that provides results ("positive, negative or indeterminate") based on predefined threshold values and calculation of "PAT scores." Human involvement is limited to sample processing and running the instrument, not interpreting raw data or making diagnostic decisions without the device's output.

7. The Type of Ground Truth Used

The primary ground truth used for both the prospective and retrospective clinical studies was bacterial culture. For discordant results in the retrospective study, PCR testing was used as a secondary, confirmatory method.

8. The Sample Size for the Training Set

The document does not explicitly state the sample size used for the training set. It mentions that "threshold values for both the L. pneumophila target DNA and the IAC were initially established using Receiver Operator Characteristic curve analyses of data obtained from positive and negative controls." These controls would constitute a form of training or calibration data, but the specific breakdown and size are not provided. The thresholds were then "verified in clinical studies and with retrospective L. pneumophila positive and negative lower respiratory specimens" and "validated in additional clinical studies."

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

The ground truth for establishing the initial threshold values (which can be considered part of the "training" or calibration) was based on positive and negative controls. The nature of these controls (e.g., cultured bacteria, synthetic DNA, confirmed clinical samples) is not detailed, but they would represent samples with known L. pneumophila presence or absence. Further verification involved "retrospective L. pneumophila positive and negative lower respiratory specimens," implying that their status (positive/negative) was also determined by a reference method, most likely culture.

Summary

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MAR - 9 2004

510(k) SUMMARY

SUBMITTED BY: BECTON, DICKINSON AND COMPANY 7 LOVETON CIRCLE SPARKS, MD 21152
COLLEEN A. KISTLER CONTACT: TELEPHONE: (410) 316-4988
PREPARED: MARCH 5, 2004
BD ProbeTec™ ET Legionella pneumophila (LP) Amplified DNA DEVICE NAME: Assay

PREDICATE

Bacterial culture methods, Bartels Legionella Urinary Antigen DEVICES: ELISA Test, Binax NOW™ Legionella Urinary Antigen Tests, Medical Diagnostic Technologies' Polyvalent Fluorescent Antibody Reagents for Legionella, Gen-Probe Legionella Rapid Diagnostic System, BD ProbeTec™ ET assays for Mycobacterium tuberculosis Complex (ctb) Culture Identification and Chlamydia trachomatis / Neisseria gonorrhoeae (CT/GC).
INTENDED USE: The BD ProbeTec™ ET Legionella pneumophila (LP) Amplified DNA Assay, for use with the BD ProbeTec™ ET System, employs Strand Displacement Amplification (SDA) technology for the direct qualitative detection of L.pneumophila DNA (serogroups 1-14) in sputum from patients with a clinical suspicion of pneumonia. It is intended to aid in the presumptive diagnosis of Legionnaires' disease in conjunction with culture and other methods.

DEVICE DESCRIPTION:

The BD ProbeTecTM ET LP Amplified DNA Assay is based on the simultaneous amplification and detection of target DNA sequences using nucleic acid primers and fluorescently-labeled detector probes in a process known as strand displacement amplification (SDA). The SDA reagents are dried in two separate disposable microwells. Processed sample containing DNA is added to a Priming Microwell, which contains the amplification primers, fluorescently-labeled detector probes, and other reagents necessary for amplification. Following incubation, the reaction mixture is transferred to an

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Amplification Microwell, which contains two enzymes (a DNA polymerase and a restriction endonuclease) necessary for SDA. The Amplification Microwells are sealed to prevent contamination and then incubated in a thermally controlled fluorescent reader, which monitors each reaction for the generation of amplified products. Each reaction coamplifies and detects an Internal Amplification Control (IAC), as well as the target DNA. The purpose of the IAC is to verify that proper conditions exist for amplification and to reduce the possibility of reporting a false negative result due to specimen inhibitors. The presence or absence of L. pneumophila DNA is determined by calculating PAT scores (Passes After Threshold) for the specimen based on predefined threshold values. The instrument automatically reports the results as positive, negative or indeterminate.

DEVICE COMPARISON:

FDA regulates assays, serological reagents, and diagnostic test systems intended to directly or indirectly, cletect antibodies, or nucleic acids for identification of Haemophilus organisms (including Legionella) as class II medical devices pursuant to 21 C.F.R. § 866.3300. Within this device classification, FDA has established three Legionella specific product codes, including: (1) "LQH" for reagents used to detect Legionella nucleic acids; (2) "MJH" for enzyme linked immunosorbent assays to detect antigens from or antibodies specific to Legionella; and (3) "LHL" for fluorescent labeled antibody reagents with specific reactivity to Legionella antigens used in direct and indirect detection methods.

The BD ProbeTec™ ET LP Amplified DNA Assay is substantially equivalent' to other legally marketed diagrostic methods and in vitro diagnostic (IVD) medical devices for the detection of L. pneumophila as an aid in the diagnosis of Legionnaires' disease. Specifically, the BD ProbeTec™ ET LP Amplified DNA Assay is a nucleic acid amplification detection assay indicated for use with sputum specimens from patients with a clinical suspicion of pneumonia as an aid in the presumptive diagnosis of Legionnaires' disease in conjunction with culture and other methods. Thus, the BD ProbeTec™ ET LP Amplified DNA Assav has the same intended use and similar indications for use as bacterial culture methods and antigen detection tests intended to detect the presence of L. pneumophila in human specimens as an aid in the diagnosis of disease.

11 The term "substantial equivalence," as used in this 510(k) notification, is limited to the definition of substantial equivalence as found in the Federal Food. Drug and Cosmetic Act, as amended and applied under 21 C.F.R. Part 807, Subpart E, under which a device can be marketed without premarket approval or reclassification. A determination of substantial equivalency under this notification is not intended to have any bearing whatsoever on the resolution of patent infringement suits or any other patent matters. No statements related to, or in support of, substantial equivalence herein shall be construed as an admission against interest under the US Patent Laws or their application by the courts.

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Additionally, the BD ProbeTec™ ET LP Amplified DNA Assay has the same principles of operation and technological characteristics of diagnostic test systems intended to detect nucleic acids from infectious organisms, such as the Gen-Probe Legionella Rapid Diagnostic System, as well as the BD ProbeTec™ ET assays for Mycobacterium tuberculosis (the "ctb" assay) and Chlamydia trachomatis!Neisseria gonorrhoege/ (or "CT/GC" assay). Specifically, the BD ProbeTec™ ET LP Amplified DNA Assay and the predicate devices are tests that employ amplification and detection of target nucleic acid regions using nucleic acid primers and fluorescently labeled detector probes. Target nucleic acids (i.e., DNA or ribosomal RNA) from specific infectious organisms in a patient's sample are anplified using specific enzymes. The amplified target molecules are detected by measuring the fluorescent signal generated by the detector probes. While the specific primers, enzymes, amplification/detection technology, fluorescent probes, and internal controls differ from test to test and organism to organism, the principles of operation for the BD ProbeTec™ ET LP Amplified DNA Assay and the predicate devices are similar.

Several minor differences exist between the BD ProbeTec™ ET LP Amplified DNA Assay and the predicate devices. For example, the BD ProbeTec™ ET LP Amplified DNA Assay detects specific nucleic acid sequences of the L. pneumophila organism, while reference culture detects only viable organisms. Similarly, urinary antigen tests detect soluble L. pneumophila serogroup 1 antigens present in human urine samples, while the BD ProbeTec™ ET LP Amplified DNA Assay detects DNA from serogroups 1 to 14 in lower respiratory specimens. Lastly, the specific primers and probes used in the BD ProbeTecTM ET LP, ctb and CT/GC Assays differ in their specificity for different nucleic acid sequences.

However, these minor differences do not raise new questions of safety and effectiveness related to the BD ProbeTec™ ET LP Amplified DNA Assay. In fact, the questions of safety and effectiveness are the same – does each test detect the presence of an infectious organism, and do the technological characteristics of each test generate a reproducible result that may be used as an aid in the diagnosis of disease. Analytical and clinical data summarized below support the position that these minor differences have no significant impact on the safety, efficacy, or performance of the assay compared to the reference and predicate methods.

SUMMARY OF PERFORMANCE DATA:

ANALYTICAL STUDIES:

The threshold values for both the L. pneumophila target DNA and the IAC were initially established using Receiver Operator Characteristic curve analyses of data obtained from positive and negative controls. These threshold values were verified in clinical studies and with retrospective L. pneumophila positive and negative lower respiratory specimens. The threshold values were then validated in additional clinical studies described below. Additional studies, including analytical sensitivity, analytical specificity, interfering substances, and reproducibility were also conducted with acceptable results.

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CLINICAL STUDIES:

Prospective Study: A prospective study evaluating the performance of the BD ProbeTec™ ET LP Amplified DNA Assay was conducted using culture at seven clinical centers within the United States and Canada during the 2002 -2003 respiratory season. A total of 406 subjects were enrolled, from whom a total of 114 sputum specimens collected from 114 patients met the criteria for inclusion in the study. In comparison to culture, 100% of the prospective sputum specimens (114/114; 95% confidence interval of 96.8% - 100%) were negative by both culture and the BD ProbeTecT™ ET LP Amplified DNA Assay. Because there were no culture positive specimens, there were insufficient data to estimate sensitivity. Therefore, a secondary retrospective analysis was conducted.

Retrospective Study: To aid in estimating assay sensitivity, the BD ProbeTec™ ET LP Amplified DNA Assay was evaluated with 83 retrospective sputum specimens acquired from clinical sites within the United States, Europe, and Canada. In comparison to culture, 23 of the 83 retrospective specimens were positive for L. pneumophila, while 60 were negative. Of these, 21 of the 23 culture positive specimens were positive in the BD ProbeTec™ ET LP Arnplified DNA Assay (21/23, 91.3% agreement; 95% confidence interval of 72% - 98.9%). Two specimens were culture positive, BD ProbeTec™ ET LP Amplified DNA Assay negative. Polymerase Chain Reaction (PCR) testing was performed on both specimens; one specimen was positive by PCR. Additionally, 52 of the 60 culture negative specimens were negative in the BD ProbeTec™ ET LP Amplified DNA Assay (52/60, 86.7% agreement; 95% confidence interval of 75.4% - 94.1%). Eight specimens were culture negative, BD ProbeTec™ ET LP Amplified DNA Assay positive. PCR testing was performed on six of the eight specimens; all six specimens were positive by PCR. Overall agreement between culture and the BD ProbeTec™ ET LP Amplified DNA Assay for the retrospective specimens was 88% (73/83; 95% confidence interval of 79% to 94.1%). The 23 culture positive specimens were distributed among the following serogroups: 47.8% (11/23) Serogroup 1; 17.4% (4/23) Serogroup 3; 13.0% (3/23) Serogroup 4; 4.3% (1/23) Serogroup 5; 4.3% (1/23) Serogroup 6 and 13% (2/23) Serogroup information not available.

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Image /page/4/Picture/1 description: The image shows the logo for the Department of Health & Human Services (HHS). The logo consists of a stylized caduceus symbol, which is a staff with two snakes coiled around it, and the text "DEPARTMENT OF HEALTH & HUMAN SERVICES USA" arranged in a circular fashion around the symbol. The caduceus is depicted in black, and the text is also in black, set against a white background.

Food and Drug Administration 2098 Gaither Road Rockville MD 20850

MAR - 9 2004

Ms. Colleen Kistler Regulatory Affairs Specialist Diagnostic Systems Becton Dickinson and Company 7 Loveton Circle Sparks, MD 21152

Re: K033861

Trade/Device Name: |BD ProbeTec™ ET Legionella pneumophila Amplified DNA Assay Regulation Number: 21 CFR 866.3300 Regulation Name: Haemophilus spp. serological reagents Regulatory Class: Class II Product Code: LQH Dated: December 11, 2003 Received: December 12, 2003

Dear Ms. Kistler:

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 clo 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 either class II (Special Controls) or class III (PMA), 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); and good manufacturing practice requirements as set forth in the quality systems (QS) regulation (21 CFR Part 820).

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Page 2

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 information about the application of labeling requirements to your device, or questions on the promotion and advertising of your device, please contact the Office of In Vitro Diagnostic Device Evaluation and Safety at (301) 594-3084. Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21CFR Part 807.97). 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) 443-6597 or at its Internet address http://www.fda.gov/cdrh/dsma/dsmamain.html.

Sincerely yours,

Salarrys

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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Indications for Use

510(k) Number (if known): K033861

Device Name: BD ProbeTec™ ET Legionella pneumophila Amplified DNA Assay

Indications For Use:

Prescription Use V (Part 21 CFR 801 Subpart D)

AND/OR

Over-The-Counter Use (21 CFR 807 Subpart C)

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

Concurrence of CDRH, Office of In Vitro Diagnostic Devices (OIVD)

Nols ath
Division Sign-Off

Office of In Vitro Diagnostic Device Evialuation and Sately

KOJJ861 510(k) _

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Regulation Number and Section

§ 866.3300

Haemophilus spp. serological reagents.(a)
Identification. Haemophilus spp. serological reagents are devices that consist of antigens and antisera, including antisera conjugated with a fluorescent dye, that are used in serological tests to identifyHaemophilus spp. directly from clinical specimens or tissue culture isolates derived from clinical specimens. The identification aids in the diagnosis of diseases caused by bacteria belonging to the genusHaemophilus and provides epidemiological information on diseases cause by these microorganisms. Diseases most often caused byHaemophilus spp. include pneumonia, pharyngitis, sinusitis, vaginitis, chancroid venereal disease, and a contagious form of conjunctivitis (inflammation of eyelid membranes).(b)
Classification. Class II (special controls). The device is exempt from the premarket notification procedures in subpart E of part 807 of this chapter subject to § 866.9.