Bartels Legionella Urinary Antigen ELISA Test is intended as an adjunct to culture for the presumptive diagnosis of past or current Legionnaires' Disease by qualitative detection of Legionella pneumophila Serogroup 1 antigen in human urine.

Device Description

Bartels Legionella Urinary Antigen ELISA Test is an enzyme-linked immunoassay intended for the qualitative detection of Legionella pneumophila Serogroup 1 antigen in human urine. The kit consists of microelisa stripwells with lid, positive and negative control reagents, conjugate, wash concentrate, colorimetric substrate (2 components) and stop solution. Sufficient materials are provided to perform 96 analyses. The microelisa wells have been pre-coated with purified rabbit antibodies to Legionella pneumophila Serotype 1 (capture antibody). An undiluted urine specimen (100 µL), or positive or negative controls (100 µL each) are each placed in a single microelisa well followed by the addition of 50 uL of Conjugate (horseradish peroxidase-conjugated rabbit antibodies to L. pneumophila). The loaded microelisa plate is then covered with the lid and incubated for 48 to 52 minutes at 34-37°C followed by 4 cycles of wash/aspiration using diluted Wash Solution (manual or automated wash procedure). Colorimetric substrate (tetramethyl benzidine/H2O2 100 µL/well) is then added and incubated for 10 to 12 minutes at 34-37℃ followed by the addition of Stop Solution (1M Phosphoric acid, 100 uL/well). The stopped plate is then read on a microelisa plate reader at 450 nm against an air blank. For a test to be considered valid, the Negative Control must have an optical density (OD) value of less than 0.100 and the Positive Control must be greater than the Positive Cutoff (pco). The pco is equal to 4X the O.D. value of the Negative Control value. Any specimen with an O.D. value ≥ the pco is considered positive. Any specimen with an O.D. value < the pco is considered negative. Alternatively, the results can be visually read. For this purpose, a visual interpretation card, and written instructions, are provided in the kit for interpretation of results. Any well that produces definite yellow color is considered to be positive.

AI/ML Overview

Here's a breakdown of the acceptance criteria and the study details for the Bartels Legionella Urinary Antigen ELISA Test, based on the provided text:

1. Table of Acceptance Criteria and Reported Device Performance

The acceptance criteria are implied by the comparison to the predicate device's performance, as the study aims to establish substantial equivalence.

Performance Metric	Predicate Device (Binax Legionella Urinary Antigen EIA)	Bartels Legionella Urinary Antigen ELISA Test (Automated Reader)	Bartels Legionella Urinary Antigen ELISA Test (Visual Interpretation)
Sensitivity	87.2%	94.7%	92.6%
Specificity	86.7%	91.1%	93.9%
Accuracy	86.9%	92.3%	93.4%

Note: The acceptance criteria for the Bartels device would be meeting or exceeding these performance characteristics, particularly in comparison to the predicate device, to demonstrate substantial equivalence. The text explicitly states that "Substantial equivalence was established between the Bartels LUA and the predicate device" and that "there is equivalence between reading the results with an automated plate reader and performing a visual interpretation."

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

Sample Size (Test Set): 274 clinically well-defined urine specimens.
- 94 urine specimens from patients whose respiratory specimens were culture-positive for Legionella pneumophila Serogroup 1.
- 150 urine specimens from patients who did not have a diagnosis of Legionella pneumophila.
- 30 urine specimens from normal healthy volunteers.
Data Provenance: The study was performed "at a major infectious disease reference laboratory." The country of origin is not specified but is likely the USA given the FDA 510(k) submission. The data is retrospective, as it uses "clinically well-defined urine specimens" which implies they were collected and characterized prior to the study.

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

The text does not explicitly state the number of experts used to establish the ground truth.
Qualifications: The ground truth for positive cases was established by "respiratory specimens were culture-positive for Legionella pneumophila Serogroup 1." This indicates that microbiology experts would have performed these cultures, which is a standard diagnostic method. For negative cases, it's based on "patients who did not have a diagnosis of Legionella pneumophila" and "normal healthy volunteers," implying clinical diagnoses and health assessments.

4. Adjudication Method for the Test Set

The text does not explicitly state an adjudication method. The ground truth appears to be based on established clinical and laboratory diagnostic methods (culture, absence of diagnosis).

5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done

No, a typical MRMC study comparing human readers with and without AI assistance was not performed.
Instead, a comparison was made for the Bartels LUA ELISA Test itself between two interpretation methods:
- Automated plate reader.
- Visual interpretation using a provided card.
Effect Size: The comparison showed that the visual interpretation had slightly different, but still strong, performance characteristics:
- Automated Reader: Sensitivity 94.7%, Specificity 91.1%, Accuracy 92.3%
- Visual Interpretation: Sensitivity 92.6%, Specificity 93.9%, Accuracy 93.4%
- The conclusion states "there is equivalence between reading the results with an automated plate reader and performing a visual interpretation."

6. If a Standalone (Algorithm Only Without Human-in-the-Loop Performance) Was Done

Yes, the performance of the Bartels Legionella Urinary Antigen ELISA Test using an automated plate reader represents a standalone algorithm-only performance. The device provides a quantitative optical density (OD) value, and the cutoff for positive/negative is applied algorithmically (OD value ≥ the pco is considered positive).

7. The Type of Ground Truth Used

Expert Consensus / Clinical Diagnosis / Pathology:
- For positive cases: Legionella pneumophila Serogroup 1 culture results from respiratory specimens (considered the "gold standard" as stated in Table 1).
- For negative cases: Patients "who did not have a diagnosis of Legionella pneumophila" and "normal healthy volunteers." This implies a combined approach of clinical assessment and likely other diagnostic tests (absence of culture results, etc.).

8. The Sample Size for the Training Set

The text does not mention a separate training set or details on its size. This device is an ELISA test, not a machine learning algorithm in the modern sense. Therefore, it does not typically undergo "training" with a distinct dataset in the way an AI model would. The "design/format" and reagent composition are developed and validated during the product development phase, and the cited clinical study is for performance validation.

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

As noted above, there isn't a specified "training set" in the context of an AI model. The development of an ELISA test involves extensive research and development to identify appropriate antibodies, optimize concentrations, and establish reaction conditions. The "ground truth" during this development phase would rely on laboratory-derived standards, cultured pathogens, and potentially internal studies with banked clinical samples to refine the assay's components and cutoff values. However, these details are not provided in this 510(k) summary.

Summary

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DEC 2 1 1999

K991074

000018

510(k) SUMMARY

A. Name of Device and Classification

Bartels Legionella Urinary Antigen ELISA Test Trade Name:

Bartels Legionella Urinary Antigen ELISA Test is an enzyme-Classification: linked immunoassay that detects Legionella pneumophila Serogroup 1 antigen in human urine. This test has been classified as a Class II (performance standards) device, product code MJH (21 CFR 866.3300).

B. Legally Marketed Device

Bartels Legionella Urinary Antigen ELISA Test claims substantial equivalence to the Binax Legionella Urinary Antigen EIA.

C. Device Description

The microelisa wells have been pre-coated with purified rabbit antibodies to Legionella pneumophila Serotype 1 (capture antibody). An undiluted urine specimen (100 µL), or positive or negative controls (100 µL each) are each placed in a single microelisa well followed by the addition of 50 uL of Conjugate (horseradish peroxidase-conjugated rabbit antibodies to L. pneumophila). The loaded microelisa plate is then covered with the lid and incubated for 48 to 52 minutes at 34-37°C followed by 4 cycles of wash/aspiration using diluted Wash Solution (manual or automated wash procedure). Colorimetric substrate (tetramethyl benzidine/H2O2 100 µL/well) is then added and incubated for 10 to 12 minutes at 34-37℃ followed by the addition of Stop Solution (1M Phosphoric acid, 100 uL/well). The stopped plate is then read on a microelisa plate reader at 450 nm against an air blank. For a test to be considered valid, the Negative Control must have an optical density (OD) value of less than 0.100 and the Positive Control must be greater than the Positive Cutoff (pco). The pco is equal to 4X the O.D. value of the Negative Control value. Any specimen with an O.D. value ≥ the pco is considered positive. Any specimen with an O.D. value < the pco is considered negative. Alternatively, the results can be visually read. For this purpose, a visual interpretation card, and written instructions, are provided in the kit for interpretation of results. Any well that produces definite yellow color is considered to be positive.

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The following components are provided in each Bartels LUA ELISA kit:

Micro Wells, 96 break-away coated wells with purified rabbit anti-Legionella 1. pneumophila Serogroup 1, IgG fraction. Ready to use. Store at 2-8°C.
Conjugate, 6.5 mL bottle of purified rabbit anti-Legionella pneumophila 2. Serogroup 1 IgG conjugated to horseradish peroxidase (HRP) in a buffer with protein stabilizer in a red tracking dye. Ready to use. Store at 2-8°C.
1. Wash Concentrate (20X), 100 mL bottle of buffered saline with detergent and thimerosal. 20X concentrate; dilute 1:20 with distilled or deionized water before use. Store at 2-30°C.
Substrate A, 12mL bottle of tetramethyl benzidine (TMB). Ready to use. 4. Store at 2-8°C.
ર . Substrate B, 12mL bottle of hydrogen peroxide (H2O2). Ready to use. Store at 2-8°C.
Stop Solution, 12mL bottle of 1M phosphoric acid. Ready to use. Store at 2-6. 30°C.
Positive Control. 1.5mL bottle of human urine containing Legionella 7. pneumophila serogroup 1 antigen and preservative. Ready to use. Store at 2-8°C.
1. Negative Control, 1.5mL bottle of normal human urine and preservative. Ready to use. Store at 2-8°C.
இ Visual Interpretation Card - Visual interpretation card displaying 5 levels of vellow color intensity.
1. Package Insert, Detailed description of test procedure and interpretation of results.

D. Intended Use

E. Comparison with the Predicate Device

Bartels Legionella Urinary Antigen ELISA Test, bv the antigen capture sandwich ELISA technique described in this application, is substantially equivalent to the currently marketed Binax Legionella Urinary Antigen EIA which has been cleared by FDA through 510(k) premarket notification. Both kits share common intended use statements, target populations, design/format. kit materials, performance characteristics, absence of risk to patients, specimen type and analytes. The following table (Table 1) summarizes the similarities

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Table 1: Comparison of Devices
Product Name	Bartels Legionella Urinary AntigenELISA Test	Binax Legionella Urinary AntigenEIA
Intended UseStatement	"Bartels Legionella Urinary AntigenELISA Test is intended as an adjunctto culture for the presumptivediagnosis of past or currentLegionnaires' Disease by qualitativedetection of Legionella pneumophilaSerogroup 1 antigen in human urine."	"This kit is an enzyme immunoassay(EIA) based system intended for invitro diagnostic use to qualitativelydetect the presence of Legionellapneumophila Serogroup 1 antigen (L.pneumophila Serogroup 1 antigen) inhuman urine as an adjunct to culturefor the presumptive diagnosis of pastor current Legionnaires' Disease."
Target Population	Individuals suspected of acuteinfection by Legionella pneumophilaSerotype 1.	Individuals suspected of acuteinfection by Legionella pneumophilaSerotype 1.
Design/format	Antigen capture (sandwich) enzymeimmunoassay.	Antigen capture (sandwich) enzymeimmunoassay.
Materials	Microelisa stripwells coated withrabbit polyclonal antibodies to L.pneumophila Serotype 1, HRPpolyclonal antibodies to L.pneumophila Serotype 1, positive andnegative controls, wash concentrate,tetramethyl benzidine/H2O2 (TMB)colorimetric substrate, stop solution,visual interpretation card, packageinsert.	Microelisa stripwells coated withrabbit polyclonal antibodies to L.pneumophila Serotype 1, HRPpolyclonal antibodies to L.pneumophila Serotype 1, positive andnegative controls, wash concentrate,tetramethyl benzidine/H2O2 (TMB)colorimetric substrate, stop solution,package insert.
PerformanceCharacteristics(Described inSection 10).	Using culture method as "goldstandard":Sensitivity: 94.7%Specificity: 91.1%Accuracy: 92.3%	Using culture method as "goldstandard":Sensitivity: 87.2%Specificity: 86.7%Accuracy: 86.9%
Risk to patient	No unique issues of safety oreffectiveness.	No unique issues of safety oreffectiveness.
Specimen Type	Voided urine.	Voided urine.
Analyte	Legionella pneumophila Serotype 1soluble urinary antigen	Legionella pneumophila Serotype 1soluble urinary antigen

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of Bartels Legionella Urinary Antigen ELISA Test and Binax Legionella Urinary Antigen EIA:

Performance Data F.

A clinical study was performed on 274 clinically well-defined urine specimens at a major infectious disease reference laboratory. The study consisted of: a) 94 urine specimens from patients whose respiratory specimens were culture-positive for Legionella pneumophila Serogroup 1; b) 150 urine specimens from who did not have a diagnosis of Legionella pneumophila; and c) 30 urine specimens from normal healthy volunteers. The Bartels Legionella Urinary Antigen ELISA Test had a sensitivity of 94.7%, specificity of 91.1% and accuracy of 92.3%. Substantial equivalence was established between the Bartels LUA and the predicate device.

In this study, a comparison was also made for the Bartels LUA ELISA Test between results obtained with the automated plate reader vs. the use of a visual interpretation card. The sensitivity of the visual interpretation was 92.6%, specificity was 93.9% and accuracy was 93.4%.

G. Conclusion

The Bartels Legionella Urinary Antigen ELISA Test is substantially equivalent to the Binax Legionella Urinary Antigen EIA. Furthermore, with the Bartels LUA ELISA Test, there is equivalence between reading the results with an automated plate reader and performing a visual interpretation.

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Confidential

Name of Submitter:

INTRACEL Corporation 1330 Piccard Dr. Rockville, MD 20850 Phone: 301-258-5200 301-296-0076 Fax:

Name of Contact Person:

Sheryl Ruppel Regulatory Affairs Manager INTRACEL Corporation 1330 Piccard Dr. Rockville, MD 20850 Phone: 301-258-5200 Ext. 1089 Fax:

March 30, 1999 Date Prepared:

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Image /page/5/Picture/1 description: The image shows the logo for the U.S. Department of Health & Human Services. The logo is a circular emblem with the department's name encircling a symbol. The symbol is a stylized representation of a human figure embracing a bird, which is meant to represent the department's mission of protecting the health of all Americans and providing essential human services.

DEC 2 1 1999

Food and Drug Administration 2098 Gaither Road Rockville MD 20850

Ms. Sheryl Ruppel Regulatory Affairs Manager INTRACEL Corporation 1330 Piccard Drive Rockville, Maryland 20850

Re: K991074 Trade Name: Bartels Legionella Urinary Antigen ELISA Test Regulatory Class: II Product Code: MJH Dated: November 19, 1999 Received: November 19, 1999

Dear Ms. Ruppel:

We have reviewed your Section 510(k) notification of intent to market the device referenced above and we 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). 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 (Premarket Approval), it may be subject to such additional controls. Existing major regulations affecting your device can be found in the Code of Federal Regulations, Title 21, Parts 800 to 895. A substantially equivalent determination assumes compliance with the Current Good Manufacturing Practice requirements, as set forth in the Quality System Regulation (QS) for Medical Devices: General regulation (21 CFR Part 820) and that, through periodic QS inspections, the Food and Drug Administration (FDA) will verify such assumptions. Failure to comply with the GMP regulation may result in regulatory action. In addition, FDA may publish further announcements concerning your device in the Federal Register. Please note: this response to your premarket notification submission does not affect any obligation you might have under sections 531 through 542 of the Act for devices under the Electronic Product Radiation Control provisions, or other Federal laws or regulations.

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Page 2

Under the Clinical Laboratory Improvement Amendments of 1988 (CLIA-88), this device may require a CLIA complexity categorization. To determine if it does, you should contact the Centers for Disease Control and Prevention (CDC) at (770)488-7655.

This letter will allow you to begin marketing your device as described in your 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 vour device to proceed to the market.

If you desire specific advice for your device on our labeling regulation (21 CFR Part 801 and additionally 809.10 for in vitro diagnostic devices), please contact the Office of Compliance at (301) 594-4588. Additionally, for questions on the promotion and advertising of your device, please contact the Office of Compliance at (301) 594-4639. Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21 CFR 807.97). Other general information on your responsibilities under the Act may be obtained from the Division of Small Manufacturers Assistance at its toll free number (800) 638-2041 or at (301) 443-6597 or at its internet address "http://www.fda.gov/cdrh/dsmamain.html"

Sincerely yours.

Steven Butman

Steven I. Gutman, M.D., M.B.A. Director Division of Clinical Laboratory Devices Office of Device Evaluation Center for Devices and Radiological Health

Enclosure

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Page_1 of_1

510(k) Number (if known): K991074

Bartels Legionella Urinary Device Name:

Antigen ELISA Test

Indications For Use:

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

Concurrence of CDRH, Office of Device Evaluation (ODE)

Woody Dubois

(Division Sign Off)
Division of Clinical Laboratory Devices
510(k) Number K991074

Prescription Use
(Per 21 CFR 801.109)

Over-The-Counter Use__________________________________________________________________________________________________________________________________________________________

(Optional Format 1-2-96)

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.