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The BD Kiestra IdentifA module is an automated in vitro diagnostic specimen preparation system for use with the BD Kiestra Laboratory Automation Solution to prepare MALDI targets for the Bruker MALDI Biotyper System (CA, sirius CA, or sirius one CA) for the qualitative identification of microorganisms using matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS) analysis of colonies grown on plated culture media from human specimens.

The BD Kiestra IdentifA is indicated for use in the clinical laboratory with the BD Kiestra ReadA Compact and Bruker MALDI Biotyper System (CA, sirius one CA) to aid in the diagnosis of bacterial and fungal infections.

The BD Kiestra™ IdentifA automates preparation of MALDI targets for the Bruker MALDI Biotyper® CA System, sirius CA system, and/or sirius one CA System that are used in clinical laboratories for identification and differentiation of organisms grown on plated media by Matrix-Assisted Laser Desorption/lonization Time-of-Flight Mass Spectrometry (MALDI-TOF MS). The system comprises of the BD Kiestra™ IdentifA module (including the associated software and onboard nephelometers and pipetting system), formic acid and automation-compatible transfer vials (for HCCA matrix and Bacterial Test Standard (BTS), which are obtained directly from Bruker and manually transferred to the vials for use on the instrument), consumables (pipette tips and cuvette arrays for preparation of organism suspensions and fluid movement), and nephelometer calibration standards (McFarland standard vials for measuring turbidity of microbial suspensions).

When identification of an organism growing on a culture medium plate is required, a technologist designates specific colonies for picking by the BD Kiestra™ IdentifA module using a digital image of the plate obtained using the BD Kiestra™ ReadA Compact module. The BD Kiestra™ IdentifA automatically suspends the designated colonized water and uses an onboard nephelometer to determine the resulting turbidity. The organism concentration is adjusted automatically by picking additional designated colonies or by appropriate dilution of the suspension to achieve a turbidity within a targeted range of McFarland values. Based on the final organism concentration, the BD Kiestra™ IdentifA pipets one or more aliquots of the microbial suspension onto a MALDI target (either reusable 48-spot or disposable 96-spot targets) and dries the spots at elevated temperature.

The BD Kiestra™ IdentifA performs the extended Direct Transfer (eDT) Sample Preparation Procedure from Bruker whereby the instrument overlays the dried sample spot on the MALDI target with formic acid and matrix. The BD Kiestra™ IdentifA also spots the BTS used for quality control of MALDI-TOF MS organism identification. Once spots are dry, the technologist manually removes the target from the BD Kiestra™ IdentifA and loads it into the Bruker MALDI Biotyper® System for analysis. Information regarding the location of each sample and BTS on the targets and the associated MALDI-TOF MS results are transmitted between the BD Kiestra™ IdentifA and Bruker MALDI Biotyper® System via the Synapsys Informatics, the main software interface, and the BD Kiestra™ BeA, the data interface hub module that communicates with all the other modules including the BD Kiestra™ IdentifA. In addition to preparing the MALDI target, if requested, the BD Kiestra™ IdentifA will also dilute the organism suspension to a standardized turbidity of 0.5 McFarland.

Modules of the BD Kiestra™ System each have their own operating software that communicates via the central BeA data interface hub module with the Synapsys user interface which in turn sends and receives information to/from the Laboratory Information System (LIS).

The BD KiestraTM ReadA or ReadA Compact module is required for use in conjunction with the BD Kiestra™ IdentifA module for image capture. Culture plate incubation may be done offline and then moved to the BD Kiestra™ ReadA or ReadA Compact module for imaging, or incubation can be done in the ReadA and then remain in the ReadA for imaging. Additional software modules (BD Synapsys Informatics and BD Kiestra™ BeA) are also required for the function of the BD Kiestra™ IdentifA, and these modules reside on the BD Kiestra™ Laboratory Automation Solution. The digital image is used by the BD Kiestra™ IdentifA for image analysis and colony designation by the operator.

The provided text outlines the performance characteristics and acceptance criteria for the BD Kiestra IdentifA device. This device is an automated in vitro diagnostic specimen preparation system for MALDI-TOF MS analysis of microorganisms. The submission focuses on demonstrating substantial equivalence to a predicate device (K191964) with the addition of the BD Kiestra ReadA camera system and the Bruker MALDI Biotyper sirius CA and sirius one CA systems.

Here's a breakdown of the requested information based on the provided document:

Acceptance Criteria and Reported Device Performance

The acceptance criteria are implicitly defined by the successful outcomes of the studies demonstrating equivalency or accuracy. The performance is reported as meeting these criteria.

Table 1: Acceptance Criteria and Reported Device Performance

Study Details:

2. Sample Size and Data Provenance:

• Study 1 (Colony Picking Accuracy):
  • Sample Size: 205 mixed cultures (Escherichia coli and Streptococcus pyogenes). 1230 colonies were picked, and 408 isolate MALDI ID results were analyzed.
  • Data Provenance: Not explicitly stated regarding country of origin, but generally, clinical device studies for FDA submissions are conducted in the US or in countries with comparable regulatory and quality standards. The data provenance is prospective as it involves experimental setup and data collection for the purpose of the study.
• Study 2 (Camera Equivalency):
  • Sample Size: 15 microorganisms, 3 dilutions (10^3, 10^4, 10^5 CFU/mL), 2 solid media types (MAC, TSA II).
    • BD Kiestra ReadA (25MP): 270 plate images (15 organisms x 3 dilutions x 2 media types x 3 systems).
    • BD Kiestra ReadA Compact (5MP): 90 plate images (15 organisms x 3 dilutions x 2 media types x 1 system).
  • Data Provenance: Not explicitly stated regarding country of origin. Prospective.
• Study 3 (Identification Accuracy - Bruker MALDI Biotyper systems):
  • Sample Size: 37 Gram-positive bacteria, Gram-negative bacteria, and yeast organisms. Two spots per suspension, tested for three days for repeatability.
  • Data Provenance: Not explicitly stated regarding country of origin. Prospective.
• Quality Control (BTS Workflow):
  • Sample Size: 102 spots (standard workflow) and 430 spots (modified workflow).
  • Data Provenance: Not explicitly stated regarding country of origin. Prospective.

3. Number of Experts Used and Qualifications:

• Study 2 (Camera Equivalency): "Three operators representative of the intended user interpreted the culture plate images and assigned a minimal morphological identification (MMI) code."
• Other Studies: The document does not specify the number or qualifications of experts (e.g., microbiologists, lab technologists) involved in establishing ground truth or performing manual inspections (like in Study 1 for visual confirmation of picking). However, for a device in microbiology, it is standard that trained laboratory personnel or microbiologists perform these tasks.

4. Adjudication Method for the Test Set:

• The document does not explicitly describe a formal adjudication method (e.g., 2+1, 3+1 consensus) for the test set results.
• For Study 2, the "Minimal Morphological Identification (MMI) code" was assigned by "three operators," and agreement was measured. It implies independent assessment rather than a consensus/adjudication process.
• For other studies, the "expected identification" or "Bruker interpretive criteria" served as the reference standard, rather than an adjudicated human consensus.

5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study:

• No MRMC comparative effectiveness study was done to show how human readers improve with AI vs. without AI assistance. This device is an automated preparation system, aiding in sample processing for subsequent human evaluation via MALDI-TOF MS results, rather than an AI diagnostic interpretation tool for images. Study 2 did involve multiple readers evaluating images from different camera systems, but it focused on camera equivalency for MMI interpretation, not on AI assistance for readers.

6. Standalone Performance:

• The device (BD Kiestra IdentifA) is an automated system for sample preparation. Its "standalone performance" is implicitly demonstrated through the accuracy of its automated functions (colony picking, suspension preparation, spotting) and the subsequent successful identification by the Bruker MALDI Biotyper systems, which are separate components. The studies confirm the accuracy of the BD Kiestra IdentifA's automated steps in preparing samples suitable for the MALDI-TOF MS system. The MALDI-TOF MS system itself has its own performance characteristics.

7. Type of Ground Truth Used:

• Study 1 (Colony Picking Accuracy):
  • Initial confirmation of picking: Visual inspection of plates and comparison to original digital images.
  • Confirmation of identification success: Bruker MALDI identification using established interpretive criteria (Log(score) values).
• Study 2 (Camera Equivalency): Minimal Morphological Identification (MMI) codes assigned by trained operators. This is a form of expert interpretation/consensus (though agreement was measured, not a formal consensus process).
• Study 3 (Identification Accuracy - Bruker MALDI Biotyper systems): Bruker interpretive criteria for species identification (Log(score) values). This relies on the established performance of the MALDI-TOF MS system and comparison of results between different versions of the system.
• Quality Control (BTS Workflow): Bruker interpretive criteria for species identification (Log(score) values) for the Bacterial Test Standard (BTS).

In summary, the ground truth for microorganism identification is based on the established MALDI-TOF MS interpretive criteria (log scores for identification confidence), as the device's role is to prepare samples for this established identification method. For colony picking and image interpretation, the ground truth is based on visual inspection, comparison to expected outcomes, and expert human interpretation (for MMI).

8. Sample Size for the Training Set:

• The document does not mention a "training set" in the context of an AI/ML model for the BD Kiestra IdentifA. This device is described as an automated specimen preparation system utilizing robotics, nephelometry, and image processing, rather than a system based on machine learning that requires a separate training phase. The studies described are performance validation studies.

9. How the Ground Truth for the Training Set was Established:

• As the document does not describe an AI/ML model with a distinct training set, this question is not applicable. The device's functionality is based on predefined algorithms and hardware performance, validated against established laboratory methods and interpretive criteria, as detailed in point 7.

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The BD Kiestra IdentifA module is an automated in vitro diagnostic specimen preparation system for use with the BD Kiestra Laboratory Automation Solution to prepare MALDI targets for the Bruker MALDI Biotyper CA System for the qualitative identification and differentiation of microorganisms using matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS) analysis of colonies grown on plated culture media from human specimens.

The BD Kiestra IdentifA is indicated for use in the clinical laboratory with the BD Kiestra Read Compact and Bruker MALDI Biotyper CA System to aid in the diagnosis of bacterial and fungal infections.

The BD Kiestra™ IdentifA is an instrument which automates picking of technologist-selected colonies from plated media and prepares a Bruker MALDI target for identification and differentiation of organisms. The BD Kiestra IdentifA includes the following components (Note: Bruker MALDI targets, Matrix and Bacterial Test Standard (BTS) are required, however, they are obtained directly from Bruker Daltonik GmbH):

• . BD Kiestra IdentifA instrument and software with onboard pipetting and nephelometry.
• . BD formic acid, deionized water, pipet tips, Matrix and BTS transfer vials.
• . BD Kiestra IdentifA nephelometer calibration standards (0.2, 0.5, 1.0 and 3.0 McFarland).
• BD Kiestra IdentifA cuvette array.

When a MALDI identification is ordered by a technologist selects the colonies from an image of a plated medium obtained using the BD Kiestra™ ReadA Compact. The coordinates of the colonies and the plated medium are transferred to BD Kiestra IdentifA where the colonies are picked. The colonies are suspended in deionized water and the onboard nephelometer determines the McFarland turbidity. Based on the McFarland, BD Kiestra IdentifA pipets the organism suspension onto a Bruker MALDI target. The BD Kiestra IdentifA uses the Bruker extended Direct Transfer method for preparation of the MALDI target by overlaying formic acid and Bruker Matrix onto the target spot. In addition, BTS spots are prepared on the target slide for quality control. Once dried, the technologist manually removes the target and loads onto the Bruker MALDI Biotyper CA System. The BD Kiestra IdentifA transfers the location of sample and BTS spots to the MALDI Biotyper CA. If requested by the technologist, BD Kiestra IdentifA will also dilute the organism suspension to a target of 0.5 McFarland.

The BD Kiestra IdentifA can be used as a standalone instrument or integrated into the BD Kiestra Laboratory Automation System. The standalone instrument utilizes an input/output module for manual plate loading, which handles de-stacking and stacking of plates. When physically integrated into the BD Kiestra Laboratory Automation System, BD Kiestra IdentifA is connected to a track by way of a connection module for automatic plate transfer. BD Kiestra IdentifA software is responsible for the instrument functionality and a touchscreen is mounted on the instrument for user interface.

Here's an analysis of the acceptance criteria and the studies performed for the BD Kiestra IdentifA device, based on the provided text:

Acceptance Criteria and Reported Device Performance

Study Details

2. Sample sizes used for the test set and the data provenance

• Colony Picking Accuracy: 200 mixed culture plates were used, from which 1200 colonies were selected and picked. The data provenance is not explicitly stated (e.g., country of origin), though it is noted as "internal analytical testing." The study design appears to be prospective (experimental).
• Organism Identification Accuracy: A total of 464 isolates of Gram-positive bacteria, Gram-negative bacteria, and yeasts were tested. The data provenance is not explicitly stated (e.g., country of origin), but it is referred to as "internal analytical testing." The study design appears to be prospective (experimental).
• Reproducibility: For each of the 15 strains, 27 tests were performed (3 days x 3 replicates x 3 instruments). This totals 15 strains * 27 tests/strain = 405 tests. The data provenance is not explicitly stated. The study design appears to be prospective (experimental).
• Limit of Detection: 9 organisms were tested, with 8 MALDI target spots inoculated for each. This totals 9 organisms * 8 spots/organism = 72 tests. The data provenance is not explicitly stated. The study design appears to be prospective (experimental).
• Cross-contamination: 100 plates inoculated with Staphylococcus aureus and 100 plates with Klebsiella pneumoniae. These 200 inoculated plates were alternated with 200 uninoculated media, for a total of 400 media processed. An additional field examination included "over 58,000 samples" processed in Europe since January 2020. The study design combined prospective experimental testing with retrospective field data analysis.

3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts

• The text does not explicitly state the number of experts or their qualifications for establishing ground truth for the test set. However, for the colony picking accuracy, it mentions "Colonies from both isolates on each plate were selected by a technologist". The "Organism Identification" study implicitly used comparison to an "expected result," which would typically be based on a validated identification method and potentially confirmed by expert review, but this is not detailed. The "Reproducibility" study used "Strains with known identifications."

4. Adjudication method for the test set

• The document does not describe a formal adjudication method (like 2+1, 3+1) for disagreements or ambiguous cases in the test set. For the "Organism Identification Accuracy," results from the BD Kiestra IdentifA were "compared to the expected result for each isolate." For colony picking, it was confirmed visually and by the Bruker MALDI Biotyper CA identification.

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 focusing on human reader performance improvement with AI assistance was not done. This device is an automated specimen preparation system, not an AI for interpretation that would assist human readers in diagnosing. Its function is to automate the preparation stage for downstream MALDI-TOF MS analysis. The comparison is between automated preparation vs. manual preparation using the predicate device.

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

• Yes, the performance studies (Colony Picking, Organism Identification Accuracy, Reproducibility, LoD, Cross-contamination) evaluate the standalone performance of the BD Kiestra IdentifA in preparing samples. The output of the BD Kiestra IdentifA is a prepared MALDI target, which is then loaded onto the Bruker MALDI Biotyper CA System for organism identification. While a technologist selects colonies from a digital image, the subsequent steps of picking, suspension, turbidity measurement, and spotting are automated without human intervention. The performance metrics are based on the results obtained from the prepared targets by the downstream MALDI-TOF MS system.

7. The type of ground truth used (expert consensus, pathology, outcomes data, etc.)

• The ground truth primarily appears to be "expected identification" or "known identifications" of microorganisms. This implies an established and validated identification for each isolate, likely obtained through standard microbiological methods or a reference MALDI-TOF MS system. For the "Organism Identification Accuracy" study, the comparison was between the BD Kiestra IdentifA prepared samples and "manual sample preparation, i.e. performing the extended Direct Transfer (eDT) Procedure and spotting on a MALDI target according to the previously FDA-cleared Bruker MALDI Biotyper CA user manual." This suggests the "expected result" was either based on prior rigorous identification or the result from the manual predicate method.

8. The sample size for the training set

• The document does not explicitly state the sample size for a training set. As an automated specimen preparation system, it's possible its internal algorithms (e.g., for colony picking, turbidity estimation, pipetting precision) were developed and optimized using various datasets, but these "training sets" are not described in terms of size or content. The provided studies focus on validation/test set performance.

9. How the ground truth for the training set was established

• Not applicable, as a specific "training set" and its ground truth establishment are not described in the provided text. The device's function is mechanical automation of a known lab procedure, not an AI model that learns from training data in the same way. Any inherent 'intelligence' (e.g., image processing for colony identification) would have been programmed based on established features rather than learned through labeled training data.

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