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The APAS Independence is an in vitro diagnostic system comprised of an instrument and software analysis module(s) for specific indications that are used to automate imaging and interpretation of microbial colonies on plates of solid culture media.

The APAS Independence, when using its urine analysis module, automates urine culture plate imaging and interpretation to detect the presence or absence of microbial growth on sheep blood and MacConkey agar culture plates that are inoculated with a 1µL sample volume. The APAS Independence, when using its urine analysis module, provides a semi-quantitative assessment of colony counts that are used as an aid in the diagnosis of urinary tract infection. All urine culture plates that are identified as positive for growth by the APAS Independence, when using its urine analysis module, must be reviewed by a trained microbiologist.

APAS Independence with Urine Analysis Module is a device designed to be used in a microbiology laboratory to automate the initial screening for the presence of growth on urine culture plates. It is an in vitro diagnostic device and has no direct contact with patients.

APAS Independence consists of an automated plate handling mechanism to move the plates through the instrument, an imaging station to capture an image of the culture plate, combined with software for analysis of the image, determination of growth and presentation of reports.

The APAS Independence with Urine Analysis Module is intended to determine whether growth is present or not, and to provide a semi-quantitative assessment of the colony count (if present). This information will then be combined with other available clinical information to screen out biological samples without growth. All other plates will be presented to a microbiologist for examination, determination of status and further testing according to conventional laboratory practice. This enables the microbiologist to focus on plates with potentially significant growth, thereby reducing the time until results can be reported.

The APAS Independence is intended to have different software modules, each of which will provide an assessment of growth for specific clinical indications. This submission covers only the APAS Independence with Urine Analysis Module. The APAS Independence with Urine Analysis Module is indicated for screening of culture plates for assessment of urinary tract infections where the urine specimens are collected and 1μl is plated onto Blood and MacConkey Agars and incubated at 35±2°C for 18 to 22 hours.

The provided text describes the acceptance criteria and the study proving the device meets these criteria for the APAS Independence with Urine Analysis Module (K183648).

1. Table of Acceptance Criteria (Implicit) and Reported Device Performance:

The document establishes substantial equivalence to a predicate device, APAS Compact with Urine Analysis Module. Therefore, the acceptance criteria are implicitly tied to the performance of the predicate device. The performance data presented focuses on agreement with the predicate.

2. Sample Size and Data Provenance for Test Set:

• Sample Size: 350 leftover clinical urine samples.
• Data Provenance: The document states "leftover clinical urine samples." The country of origin is not explicitly stated but is implicitly Australia, given the submitter's country for the predicate device's de novo application (DEN150059) was Australia. The data is retrospective as it uses "leftover clinical urine samples."

3. Number of Experts and Qualifications for Ground Truth for Test Set:

Not applicable for this section as the study's ground truth for the comparison was the predicate device's performance, not human expert consensus, for the new device's equivalence study.

4. Adjudication Method for the Test Set:

Not applicable. The study compares the new device (APAS Independence) to the predicate device (APAS Compact) itself, not to human expert reads requiring adjudication. Discrepancies between the two devices are analyzed, and the clinical implications (e.g., misclassification leading to microbiologist review) are discussed.

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

• Was it done? No, an MRMC study comparing human readers with and without AI assistance was not conducted directly for the APAS Independence with Urine Analysis Module in this submission.
• The document states that the predicate device (APAS Compact with Urine Analysis Module) had three clinical studies (LBT001, LBT002, LBT003) submitted for its de novo applicationDEN150059, which "showed that APAS performed similarly to a microbiologist in reading and interpreting agar plates." This indicates that the predicate device's performance was evaluated against human microbiologists. The current submission established equivalence to this predicate.
• Effect Size: Not applicable since an MRMC study was not performed as part of this specific submission.

6. Standalone (Algorithm Only) Performance:

• Was it done? Yes, the entire study presented for the APAS Independence with Urine Analysis Module is a standalone (algorithm only) performance comparison between the new device and the predicate device. Both the APAS Independence and the APAS Compact are automated systems that read and interpret images without direct human intervention in the initial classification process.

7. Type of Ground Truth Used:

The ground truth for the APAS Independence performance evaluation was the performance of the predicate device (APAS Compact with Urine Analysis Module). The study aimed to demonstrate that the new device performs equivalently to the already-cleared predicate.

8. Sample Size for the Training Set:

The document does not explicitly state the sample size for the training set of the APAS Independence with Urine Analysis Module. It only details the test set used for the comparison with the predicate device (350 samples). However, it mentions that both devices "utilize the same core APAS technology and the same urine analysis module," implying shared underlying algorithmic development and training.

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

The document does not provide details on how the ground truth for the training set (if any specific to APAS Independence's development rather than its use of the predicate's technology) was established. However, given that the "same core APAS technology and the same urine analysis module" are utilized as the predicate, it is highly likely that the training methodologies and ground truth establishment for the predicate device would apply. For the predicate device (APAS Compact), the clinical studies (LBT001, LBT002, LBT003) referenced for the de novo application would have established ground truth, likely through expert consensus of microbiologists, as it stated "APAS performed similarly to a microbiologist."

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The APAS Compact is an in vitro diagnostic system comprised of an instrument for automated imaging of agar culture plates and a software analysis module for the following use:

The APAS Compact, when using its urine analysis module, automates urine culture plate imaging and interpretation to detect the presence of microbial growth on sheep blood and MacConkey agar culture plates that are inoculated with a 1uL sample volume. The APAS Compact, when using its urine analysis module, provides a semiquantitative assessment of colony counts that are used as an aid in the diagnosis of urinary tract infection. All urine culture plates that are identified as positive for growth by the APAS Compact, when using its urine analysis module, must be reviewed by a trained microbiologist.

The APAS Compact with Urine Analysis Module is an instrumented system that is designed for screening of urine culture plates for the presence of microbial growth. The device comprises an imaging station for capture of digital images of the culture plates, together with software for analysis of the images, the determination and enumeration of microbial growth and reporting of results.

This document outlines the acceptance criteria and study findings for the APAS Compact with Urine Analysis Module.

1. Acceptance Criteria and Reported Device Performance

2. Sample Sizes and Data Provenance

• Test Set (Clinical Study):

  • Total Enrolled Samples: 10,100 urine samples (5835 from Site 1, 2117 from Site 2, 2148 from Site 3).
  • Included in Performance Analysis: 9,224 samples (5634 from Site 1, 1769 from Site 2, 1821 from Site 3).
  • Data Provenance: Three clinical sites: one in the US (Site 1) and two ex-US (Sites 2 and 3). The study used remnant urine samples from standard of care culture. This indicates a retrospective data collection approach for the clinical study.

• Training Set: The document does not explicitly state the sample size for the training set.

3. Number of Experts and Qualifications for Ground Truth (Test Set)

• Number of Experts: Three microbiologists.
• Qualifications: "Trained microbiologist" is mentioned multiple times. For the clinical study, each microbiologist was "trained to read the urine culture plates in a standard fashion." Specific years of experience are not provided.

4. Adjudication Method (Test Set)

• The document states that for the reference method in the clinical study, "each microbiologist... was blinded to the results from the other panel members and to those obtained by the APAS Compact."
• The ground truth for the clinical study was established by a "reference microbiologist panel," meaning the consensus among these three microbiologists. The exact method of achieving consensus (e.g., 2+1, 3+1, none) is not explicitly detailed, but it implies a shared understanding to form the "reference method."

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

• No, a MRMC comparative effectiveness study was not done. The clinical study compared the APAS Compact's performance against a panel of microbiologists (serving as the reference standard), not against human readers with and without AI assistance to measure improvement. The primary goal of the APAS Compact is to automate initial screening to reduce microbiologist workload, rather than directly augment human reading for every plate.

6. Standalone Performance Study

• Yes, a standalone performance study was done. The entire clinical study (Section L.3) and analytical performance studies (Section L.1) evaluate the APAS Compact's performance as an algorithm-only device (without human-in-the-loop during the initial assessment and designation phase). The performance tables (e.g., Tables 19-24) directly report the APAS Compact's designations and colony counts compared to the reference standard. While the device's indications for use emphasize that growth-positive plates "must be reviewed by a trained microbiologist," the reported performance metrics are for the algorithm's initial assessment before this mandatory human review.

7. Type of Ground Truth Used

• Clinical Study: Expert Consensus (Microbiologist Panel): The ground truth for the clinical study was established by "an independent panel of three microbiologists," who read the urine culture plates in a "standard fashion" and were blinded to other results. Their combined assessment served as the reference method.
• Analytical Study (Linearity/Assay Reportable Range): Expert Consensus (Manual Colony Counts): The mean of two independent manual colony counts performed by two microbiologists was used as the reference result for each plate.

8. Sample Size for the Training Set

• The document does not explicitly state the sample size for the training set. It describes the "APAS Controller Software" and "Urine Analysis Module Software" functions, implying that these algorithms were developed and likely trained, but the specific training data volume is not provided in this excerpt.

9. How Ground Truth for the Training Set Was Established

• The document does not explicitly describe how the ground truth for the training set was established. While it details the methods for establishing ground truth in the analytical and clinical validation studies (using expert microbiologist consensus), it does not provide information specific to the data used for training the algorithms.

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