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The FilmArray Gastrointestinal (GI) Panel is a qualitative multiplexed in vitro diagnostic test intended for use with FilmArray systems. The FilmArray GI Panel is capable of the simultaneous detection and identification of nucleic acids from multiple bacteria, viruses, and parasites directly from stool samples in Cary Blair transport media obtained from individuals with signs and/or symptoms of gastrointestinal infection. The following bacteria (including several diarrheagenic E. coli/Shigella pathotypes), parasites, and viruses are identified using the FilmArray GI Panel:

• Campylobacter (C. jejuni/C. coli/C. upsaliensis)
• Clostridium difficile (C. difficile) toxin A/B
• Plesiomonas shigelloides
• Salmonella
• Vibrio (V. parahaemolyticus/V. vulnificus/V. cholerae) including specific identification of Vibrio cholerae
• Yersinia enterocolitica
• Enteroaggregative Escherichia coli (EAEC)
• Enteropathogenic Escherichia coli (EPEC)
• Enterotoxigenic Escherichia coli (ETEC) lt/st
• Shiga-like toxin-producing Escherichia coli (STEC) stx1/stx2 (including specific identification of the E. coli 0157 serogroup within STEC)
• Shigella/Enteroinvasive Escherichia coli (EIEC)
• Cryptosporidium
• Cyclospora cayetanensis
• Entamoeba histolytica
• Giardia lamblia (also known as G. intestinalis and G. duodenalis)
• Adenovirus F 40/41
• Astrovirus
• Norovirus GI/GII
• Rotavirus A
• Sapovirus (Genogroups I, II, IV, and V)

The FilmArray GI Panel is indicated as an aid in the diagnosis of specific agents of gastrointestinal illness and results are meant to be used in conjunction with other clinical, laboratory, and epidemiological data. Positive results do not rule out co-infection with organisms not included in the FilmArray GI Panel. The agent detected may not be the definite cause of the disease.

Concomitant culture is necessary for organism recovery and further typing of bacterial agents.

This device is not intended to monitor or guide treatment for C. difficile infection.

Due to the small number of positive specimens collected for certain organisms during the prospective clinical study, performance characteristics for E. coli O157, Plesiomonas shigelloides, Yersinia enterocolitica, Astrovirus, and Rotavirus A were established primarily with retrospective clinical specimens.

Performance characteristics for Entamoeba histolytica, and Vibrio (V. parahaemolyticus, V. vulnificus, and Vibrio cholerae) were established primarily using contrived clinical specimens.

Negative FilmArray GI Panel results in the setting of clinical illness compatible with gastroenteritis may be due to infection by pathogens that are not detected by this test or noninfectious causes such as ulcerative colitis, irritable bowel syndrome, or Crohn's disease.

A gastrointestinal microorganism multiplex nucleic acid-based assay also aids in the detection and identification of acute gastroenteritis in the context of outbreaks.

The FilmArray Gastrointestinal (GI) Panel is a multiplex nucleic acid test designed to be used with FilmArray systems. The FilmArray GI pouch contains freeze-dried reagents to perform nucleic acid purification and nested, multiplex PCR with DNA melt analysis. The FilmArray Gastrointestinal (GI) Panel simultaneously conducts 22 tests for the identification of GI pathogens from stool specimens collected in Cary Blair transport medium (Table 1). Results from the FilmArray GI Panel test are available within about one hour.

A test is initiated by loading Hydration Solution into one port of the FilmArray pouch and a stool sample (in Cary Blair transport medium) mixed with the provided Sample Buffer into the other port of the FilmArray GI pouch and placing it in the FilmArray Instrument. The pouch contains all of the reagents required for specimen testing and analysis in a freeze-dried format; the addition of Hydration Solution and sample/Sample Buffer Mix rehydrates the reagents. After the pouch is prepared, the FilmArray Software guides the user though the steps of placing the pouch into the instrument, scanning the pouch barcode, entering the sample identification, and initiating the run.

The FilmArray instrument contains a coordinated system of inflatable bladders and seal points. which act on the pouch to control the movement of liquid between the pouch blisters. When a bladder is inflated over a reagent blister, it forces liquid from the blister into connecting channels. Alternatively, when a seal is placed over a connecting channel it acts as a valve to open or close a channel. In addition, electronically controlled pneumatic pistons are positioned over multiple plungers in order to deliver the rehydrated reagents into the blisters at the appropriate times. Two Peltier devices control heating and cooling of the pouch to drive the PCR reactions and the melt curve analysis.

Nucleic acid extraction occurs within the FilmArray pouch using mechanical and chemical lysis followed by purification using standard magnetic bead technology. After extracting and purifying nucleic acids from the unprocessed sample, a nested multiplex PCR is executed in two stages. During the first stage, a single, large volume, highly multiplexed reverse transcription PCR (rt-PCR) reaction is performed. The products from first stage PCR are then diluted and combined with a fresh, primer-free master mix and a fluorescent double stranded DNA binding dye (LC Green® Plus, BioFire Defense, LLC). The solution is then distributed to each well of the array. Array wells contain sets of primers designed specifically to amplify sequences internal to the PCR products generated during the first stage PCR reaction. The 2nd stage PCR, or nested PCR, is performed in each well of the array. At the conclusion of the 2rd stage PCR, the array is interrogated by melt curve analysis for the detection of signature amplicons denoting the presence of specific targets. A digital camera placed in front of the array captures fluorescent images of the PCR2 reactions and software interprets the data.

The FilmArray software automatically interprets the results of each DNA melt curve analysis and combines the data with the results of the internal pouch controls to provide a test result for each organism on the panel.

Here's a breakdown of the acceptance criteria and study information for the FilmArray Gastrointestinal Panel (GI) for use with FilmArray Torch, based on the provided text:

1. Table of Acceptance Criteria and Reported Device Performance

The document does not explicitly state pre-defined acceptance criteria (e.g., a specific percentage for sensitivity or specificity) for the FilmArray GI Panel. However, the study aims to demonstrate reproducible detection at LoD (Limit of Detection) for each analyte and agreement with expected negative results.

Note: For Giardia lamblia, the performance was <95% detection at LoD, but this was attributed to lower than expected organism levels in the prepared samples, as comparison testing on original FilmArray systems also yielded <95%.

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

• Sample Size for Test Set: 96 total replicates per analyte. (Each analyte was tested 32 replicates per system on 3 systems).
• Data Provenance: The samples were "contrived samples containing each FilmArray GI analyte at low positive levels (1x LoD)". This indicates that the data was generated experimentally in a controlled environment, rather than being derived from real patient samples (retrospective or prospective). The country of origin is not specified but implied to be the US given the submission to the FDA.

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

Not applicable. The ground truth for the contrived samples was established by the known concentration of the analytes (low positive levels, 1x LoD) that were spiked into the samples. Expert review for ground truth is typically relevant for studies involving real patient data with diagnostic uncertainty.

4. Adjudication Method for the Test Set

Not applicable. As the test set consisted of contrived samples with known concentrations, there was no need for an adjudication method. The expected outcome for each sample was predetermined (detected or not detected).

5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study was done

No, an MRMC comparative effectiveness study was not done. This study focuses on the analytical performance of the device (FilmArray GI Panel on FilmArray Torch) compared to the predicate device, not on human reader performance with or without AI assistance. The device is an in vitro diagnostic test, not an imaging or interpretation aid.

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

Yes, this study is inherently a standalone performance evaluation of the FilmArray GI Panel on the FilmArray Torch instrument. The device is fully automated, performing nucleic acid purification, PCR, and result interpretation without human intervention in the result generation process. "Automated test interpretation and report generation. User cannot access raw data" is explicitly stated.

7. The Type of Ground Truth Used

The ground truth used for this specific study was known concentrations of analytes in contrived samples. This means the samples were engineered to contain a specific target (or not) at a specific concentration (1x LoD).

8. The Sample Size for the Training Set

The document does not explicitly mention a separate "training set" or its size for the FilmArray GI Panel on FilmArray Torch. This study is focused on validating the performance of the existing FilmArray GI Panel (reagent kit unchanged) when used with a new instrument system (FilmArray Torch). The original FilmArray GI Panel (predicate device K143005) would have undergone its own development and validation, which would likely have involved training sets, but that information is not provided in this specific document.

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

Not applicable in this document, as a training set for the FilmArray GI Panel on FilmArray Torch is not described. If a training set was used for the development of the original FilmArray GI Panel, its ground truth would have been established through methods like:

• Clinical culture: For bacterial and fungal pathogens.
• PCR or sequencing: For viruses and parasites, often considered the gold standard for nucleic acid detection.
• Electron microscopy or immunoassay: For some viral targets.
• Expert consensus: In cases of diagnostic ambiguity, though less common for molecular diagnostics where a positive/negative result is expected from a reference method.

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