(265 days)
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.
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
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.
§ 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.