(210 days)
BD BACTEC™ Plus Aerobic/F Culture Vials are used in a qualitative procedure for the aerobic culture and recovery of microorganisms (bacteria and yeast) from blood. The principal use of this medium is with the BD BACTECTM fluorescent series instruments.
The BD BACTECTM Plus Aerobic/F Culture Vials contain a bacterial growth medium intended for use in the qualitative culture and recovery of aerobic microorganisms (bacteria and yeast) from blood. It has been designed for blood volumes of three (3) to ten (10) milliliters and is used specifically with the BD BACTEC™ fluorescent-series instruments in monitoring of clinical blood specimens for the presence of microorganisms.
BD BACTECTM Plus Aerobic/F Culture Vials are supplied in a carton containing 50 vials. It is a nonsterile product.
This document describes the performance assessment of the BD BACTEC™ Plus Aerobic/F Culture Vials, a modified device, against a predicate device (K113558) to establish substantial equivalence.
Here's a breakdown of the acceptance criteria and study details:
1. Table of acceptance criteria and the reported device performance:
The document doesn't explicitly state quantitative acceptance criteria in a dedicated table format with precise thresholds. Instead, it describes comparative "acceptance criteria" through statements of "no statistically relevant difference" or "no significant differences" between the modified and predicate devices for various analytical performance metrics.
However, based on the study findings, we can infer the implicit acceptance criteria:
| Acceptance Criteria (Inferred) | Reported Device Performance (Summary from Tables 2, 3, 4, 5, 6) |
|---|---|
| Instrument Time to Detection (TTD): No statistically relevant difference in TTD between the modified and predicate device. | For the majority of organisms and conditions, the TTD difference between the modified and predicate device was very small, with 95% confidence intervals often spanning zero or indicating minor differences. Two isolates (Rothia mucilaginosa and Stenotrophomonas maltophilia) initially showed >10% difference in favor of the predicate, but further testing demonstrated this was strain-specific, not species-specific. The overall bootstrap analysis across all organisms showed negligible differences in TTD (e.g., -0.002 to -0.168 hours). |
| Percent Recovery (Sensitivity): No statistically relevant difference in recovery between the modified and predicate device. | Across all organisms, inoculum levels, and blood volumes, the percent recovery for both the predicate and modified devices was overwhelmingly 100%. In cases of lower inoculum levels (0-1 CFU), where recovery rates were expectedly lower, the differences between the two devices were generally small and varied in which device had slightly higher recovery, indicating no consistently better or worse performance. The overall recovery rates for 10-100 CFU were 100% for both devices. |
| False Negative Rate: No false negative vials observed. | Reported: 0% false negative vials for both devices. All instrument-negative vials did not yield growth upon terminal subculture. |
| False Positive Rate: No false positive vials observed. | Reported: 0% false positive vials for both devices. All vials inoculated with sterile human blood remained negative. |
| Instrument Compatibility: No significant differences in TTD and recovery across different BACTEC™ Fluorescent Series Instruments. | Reported: No recovery failures in any of the instruments (BACTEC™ FX, FX40, 9240, 9050) for either device. No significant TTD differences observed across the instruments (e.g., TTD differences generally close to zero with narrow 95% CIs). |
| Resin Performance (Antimicrobial Neutralization Capability): No statistically significant difference in recovery between lot pairs for different antimicrobial/organism combinations. | Reported: Minor variations in percent recovery between individual lots of the predicate and modified devices (e.g., Predicate Lot A: 47.77%, Modified Lot A: 47.13%). The combined data for all lots showed a very similar overall recovery (Predicate: 48.78% vs. Modified: 48.78% based on the provided table). The document explicitly states "There was no statistically significant difference observed between lot pairs." |
2. Sample sized used for the test set and the data provenance:
-
Sample Size (Test Set):
- Instrument Time to Detection & Percent Recovery:
- For 44 organisms at 10-100 CFU/vial: 264 vials per device (3 lots x 2 blood volumes x 44 organisms).
- For 15 organisms at 0-1 and 1-10 CFU/vial: 45 vials per device per inoculum level per blood volume on BACTEC™ FX, totaling 90 vials per device for these specific conditions.
- Total vials for TTD/Recovery: Approximately 444 vials per device (264 + 90 + 90).
- False Negative Rate: "115 instrument negative vials (57 in the modified device and 58 in the predicate device)" out of the 444 total vials from the TTD/Recovery study that were instrument negative.
- False Positive Rate: 120 vials per device (3 lots x 8 replicates x 5 blood volumes).
- Instrument Compatibility:
- BACTEC™ FX and FX40: 264 paired sets per instrument (total 528 paired sets).
- BACTEC™ 9240 and 9050: 96 paired sets per instrument (total 192 paired sets).
- Resin Performance: 314 antibiotic/organism combinations per lot per device. With 3 lots per device, this amounts to 942 vials per device. Overall, 1884 vials for this study.
- Instrument Time to Detection & Percent Recovery:
-
Data Provenance: The studies were retrospective analytical performance studies, comparing a modified device to a previously cleared predicate device. The information does not specify the country of origin of the data, but given it's an FDA submission for a Becton, Dickinson and Company product, it is likely based on studies conducted in the US or in compliance with US regulatory standards. The testing involved controlled laboratory conditions using spiked (inoculated) blood samples, not clinical patient samples.
3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts (e.g., radiologist with 10 years of experience):
This study is an analytical performance study for a microbial growth monitor. The "ground truth" for the test set (i.e., whether growth occurred and what the TTD was) was established by:
- Direct Inoculation: Precise quantities (CFU/vial) of known bacterial and yeast organisms were inoculated into the vials.
- Instrument Detection: The BD BACTEC™ fluorescent series instruments automatically detect and log growth (CO2 production) as part of their function.
- Terminal Subculture: For vials that remained negative, a terminal subculture was performed to confirm the absence of viable microorganisms.
Therefore, this type of study does not rely on human experts to "establish ground truth" in the way a diagnostic imaging study might require radiologists. The ground truth is determined by the experimental design (known inoculum) and the objective readings of the instrument, verified by standard microbiological techniques (subculture).
4. Adjudication method (e.g., 2+1, 3+1, none) for the test set:
Not applicable. As described above, the ground truth is established by controlled inoculation and objective instrument readings/terminal subculture, not by human interpretation or 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:
Not applicable. This is an analytical performance study of a microbial growth medium and instrument system, not a clinical study involving human readers interpreting diagnostic images or data with or without AI assistance. The device is not an AI-powered system that assists human readers.
6. If a standalone (i.e., algorithm only without human-in-the-loop performance) was done:
The device (BD BACTEC™ Plus Aerobic/F Culture Vials) is a component of an automated system (BD BACTEC™ fluorescent series instruments). The performance evaluated in this submission is effectively the "standalone" performance of the altered vial formulation within the automated BACTEC™ system, without direct human intervention in the detection process itself. Human involvement comes in collecting blood, inoculating vials, and interpreting the instrument's final positive/negative results. The study inherently assesses the algorithm (instrument's detection logic) as part of the overall system performance.
7. The type of ground truth used (expert consensus, pathology, outcomes data, etc):
The ground truth used was controlled laboratory inoculation with known quantities of specific microorganisms, followed by objective instrument detection (fluorescence changes indicating CO2 production) and confirmation by terminal microbiological subculture for negative vials. This is a highly controlled "gold standard" for analytical performance in microbiology.
8. The sample size for the training set:
Not applicable. This is an analytical performance study comparing a modified in vitro diagnostic device component to a predicate device. It does not involve a "training set" in the context of machine learning model development. The study design is focused on demonstrating functional equivalence through empirical testing.
9. How the ground truth for the training set was established:
Not applicable, as there was no training set in the context of machine learning.
§ 866.2560 Microbial growth monitor.
(a)
Identification. A microbial growth monitor is a device intended for medical purposes that measures the concentration of bacteria suspended in a liquid medium by measuring changes in light scattering properties, optical density, electrical impedance, or by making direct bacterial counts. The device aids in the diagnosis of disease caused by pathogenic microorganisms.(b)
Classification. Class I. With the exception of automated blood culturing system devices that are used in testing for bacteria, fungi, and other microorganisms in blood and other normally sterile body fluids, this device is exempt from the premarket notification procedures in subpart E of part 807 of this chapter.