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For in vitro diagnostic use with the CARESIDE Analyzer to quantitatively measure GGT from anti-coagulated whole blood, plasma, or serum specimens to aid in the diagnosis and treatment of liver diseases such as alcoholic cirrhosis and primary and secondary liver tumors.

CARESIDE® GGT cartridges are used with the CARESIDE Analyze® to measure GGT activity in anti-coagulated whole blood, plasma or serum specimens. The CARESIDE GGT cartridge, a single use disposable in vitro diagnostic test cartridge, aids in specimen separation and delivers a measured volume of plasma or serum to a dry film to initiate the measurement of GGT activity. The patented film cartridge contains all reagents necessary to measure GGT activity.

Each CARESIDE® GGT cartridge consists of a GGT-specific multi-layer reagent film mounted in a plastic base with a hinged lid. The user introduces the anti-coagulated whole blood, serum. or plasma specimen into the cartridge sample well, closes the lid and inserts the cartridge into the CARESIDE Analyzer.

Once loaded, the CARESIDE Analyzer scans the cartridge barcode, brings the cartridge and the contained specimen to 37℃, and spins the cartridge to move the sample from the sample deposition well into the cartridge channels and chambers. As the cartridge continues to spin, the blood cells are separated from the plasma/serum and the cells accumulate in the separation well. Approximately 8.5 microliters of plasma (or serum, as applicable) remain in the metering passage. Any excess sample flows into an overflow well.

The plasma (or serum, as applicable) is automatically dispensed onto the multi-layer reagent film. The spreading and substrate layer distributes the GGT containing specimen uniformly. The GGT in the specimen reacts with the substrate L-y-glutamyl-p-nitroanilide to release p-nitroaniline resulting in a change in film color. The rate of change of color intensity, as measured by the amount of reflected light at 425 nanometers, directly relates to the specimen GGT activity.

As the cartridges spin, photodiodes measure reflectance of light emitted by wavelengthspecific light emitting diodes (LEDs) over a fixed time period. The instrument uses the reflectance measurements and the lot-specific standard curve to calculate GGT activity.

Here's an analysis of the acceptance criteria and study information for the CARESIDE® GGT device, based on the provided text:

Acceptance Criteria and Reported Device Performance

Note: The document explicitly states that the CARESIDE® GGT is "substantially equivalent in principle, intended use, and clinical performance to the currently marketed Vitros slides for the quantitative measurement of GGT on the Vitros DTSC 60 II." This broad statement acts as the overarching acceptance criterion, with the detailed performance characteristics providing the evidence for this claim. The differences (e.g., direct whole blood specimen, no accurate pipetting required, no reagent pre-warming required for CARESIDE® GGT) are presented as differences rather than failures of acceptance, implying they are either improvements or clinically insignificant for the intended use.

Study Details

1. Sample size used for the test set:

   • The document does not explicitly state the sample size (number of patient samples) used for the comparison studies (accuracy, precision, method comparison, interference, specimen type evaluation).
   • Data provenance: Not explicitly stated, but clinical data is implied for "Method Comparison" and "Specimen Types & Anticoagulants" by comparing against other analyzers and evaluating different sample types. Given the context of a 510(k) summary, it's highly likely to be prospective testing for the CARESIDE device.

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

   • This information is not provided in the document. For an in vitro diagnostic device measuring an analyte (GGT), the "ground truth" is typically established by reference laboratory methods or a predicate device.

3. Adjudication method (e.g., 2+1, 3+1, none) for the test set:

   • This is not applicable for this type of in vitro diagnostic device study. Adjudication methods like 2+1 or 3+1 are typically used in imaging or clinical trials involving subjective expert interpretation to resolve discrepancies. For quantitative laboratory tests, the "ground truth" is typically a quantitative value from a reference method or predicate device, not subject to subjective expert interpretation requiring adjudication.

4. If a multi-reader multi-case (MRMC) comparative effectiveness study was done, what was the effect size of how much human readers improve with AI vs without AI assistance:

   • This is not applicable. The CARESIDE® GGT is an in vitro diagnostic device to measure GGT activity, not an AI-assisted diagnostic tool requiring human interpretation. Therefore, an MRMC study or assessment of human reader improvement with AI assistance is not relevant.

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

   • Yes, the performance characteristics (accuracy, precision, linearity, interference, method comparison) are inherently "standalone" in that they describe the performance of the CARESIDE® GGT device and analyzer system directly, without requiring human-in-the-loop performance assessment to determine the GGT value. The device provides a quantitative result.

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

   • The "ground truth" for the CARESIDE® GGT performance evaluation is established by:
     • Reference laboratory methods: For the "Method Comparison," it states "CARESIDE = 1.00 (BM/Hitachi 902 GGT) + 0.91 U/L, r= 1.00", indicating a comparison against a commercially available clinical chemistry analyzer (BM/Hitachi 902 GGT), which serves as a reference or predicate method.
     • Known concentrations: For "Accuracy" (mean recovery 101%) and "Linearity" (by dilution), the ground truth would be known concentrations of GGT in control materials or diluted samples.
     • Predicate device comparison: The overall claim of substantial equivalence to the Vitros GGT DT Slides implies that the Vitros system values served as a de facto "ground truth" or comparator for aspects of clinical performance.

7. The sample size for the training set:

   • The document does not specify a separate "training set" or its sample size. For an IVD device like this, the calibration data (bar-coded on each cartridge) effectively serves as the "training" for the device to interpret raw signals into GGT activity. However, this is distinct from statistical machine learning model training sets.

8. How the ground truth for the training set was established:

   • As above, explicitly defined "training set" in a machine learning sense is not described. However, for the calibration of the device, the ground truth would have been established using calibrators with known GGT concentrations, typically verified against reference methods. The document mentions "Calibration information bar-coded on each cartridge. Calibration information may change with each lot." This indicates that each lot is calibrated, likely against reference standards, to ensure accurate GGT measurement.

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For in-vitro diagnostic use. For the quantitative determination of gamma glutamyltransferase in serum.

Elevated serum gamma glutamyltransferase (GGT) is found in chronic alcoholism, diabetes, certain neurological disorders, and all forms of liver disease. It is more sensitive than alkaline phosphatase, the transaminases, and leucine aminopeptidase (LAP) in detecting obstructive jaundice, cholangitis, and cholecystitis; its rise occurs earlier than these other enzymes and persists longer. Moderate increases are seen with infectious hepatitis, and normal levels are seen in skeletal disease. Serum GGT levels can therefore be used to differentiate skeletal or hepatobiliary disease.

The intended use is the same as the predicate device.

The method is based on the reaction wherein gamyl glutamyltransferase catalyzes the transfer of the glutamyl group from L-g-glutamyl-3-carboxy-4-nitroanilide to glycylglycine with the formation of g-glutamylglycylglycine and 5-amino-2-nitrobenzoate. The rate of increase of 5-amino-2-nitrobenzene, which absorbs light at 405 nM. is proportional to the gamma glutamyltransferase activity in the sample.

1. Acceptance Criteria and Reported Device Performance:

2. Sample Size and Data Provenance:

The provided text focuses on the performance characteristics of the device and its comparison to a predicate device. It does not explicitly state the sample sizes used for the testing of linearity, precision, sensitivity, or interference studies. The data provenance is also not specified (e.g., country of origin, retrospective or prospective).

3. Number and Qualifications of Experts for Ground Truth:

Not applicable. This is an in vitro diagnostic device for quantitative determination of an enzyme, not an imaging or diagnostic AI tool that requires expert interpretation for ground truth establishment.

4. Adjudication Method:

Not applicable. See point 3.

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

Not applicable. This is not a comparative effectiveness study involving human readers and AI for diagnostic tasks. It's a comparison of an in vitro diagnostic assay to a predicate device.

6. Standalone Performance:

Yes, the provided data describes the standalone performance of the Data Medical Associates device through various non-clinical tests (linearity, precision, shelf-life, sensitivity, interferences, expected values). This data represents the performance of the algorithm/reagent without human intervention in the measurement process.

7. Type of Ground Truth Used:

The "ground truth" for the performance characteristics described here would be established through laboratory reference methods, calibrated standards, and known concentrations of analytes.

• Linearity: Determined by assaying samples with known, varying concentrations of GGT and ensuring the measured values are proportional.
• Precision: Determined by repeated measurements of samples with known GGT concentrations.
• Sensitivity: Determined by measuring the lowest detectable concentration of GGT using established methods.
• Interferences: Determined by spiking samples with known concentrations of potential interfering substances (bilirubin, hemoglobin, triglycerides) and observing their effect on GGT measurements compared to unspiked controls.
• Expected Values: Established through studies of a healthy reference population using validated methods.

8. Sample Size for the Training Set:

Not applicable. This is not a machine learning or AI-driven device in the sense of requiring a "training set." The device is a chemical reagent method.

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

Not applicable. See point 8.

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