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This assay is for the qualitative determination of galactose-1-phosphate uridyl transferase (GALT) activity in dried blood spot samples. Measurements of GALT are used in the diagnosis and treatment of the hereditary disease galactosemia (disorder of galactose metabolism) in infants. For in vitro diagnostic use only.

The Microplate Neonatal GALT assay utilizes dried blood spot samples (DBS) eluted in a medium containing 8-nicitinamide adenine dinucleotide phosphate (NADP), galactose-1phosphate, uridine-5-diphosphoglucose (UDPG), and a tetrazolium salt. During elution, GALT present in the specimen converts galactose-1-phosphate to glucose-1-phosphate, with the eventual reduction of NADP to NADPH. After elution, an aliquot of the eluate is transferred to a microwell. The optical density (OD) is read, then Enzyme Reagent is added. During the incubation that follows, the Enzyme Reagent converts NADPH generated by GALT and endogenous red cell enzymes to NADP, and the tetrazolium salt to a colored formazan dye which is detected at 550 or 570 nm. The OD is read again and the difference between the two OD readings is determined. GALT activity, in units/g hemoglobin or units/liter blood, is calculated from the difference in signal between the two absorbance readings. A unit is defined as the quantity of GALT that catalyzes the formation of 1 micromole of UDP galactose per gram of hemoglobin or per Liter blood per hour at 37℃. An external calibrator is not necessary because enzyme activity is measured directly with substrates in excess.

Here's a breakdown of the acceptance criteria and the study information for the Microplate Neonatal GALT assay, based on the provided document:

Acceptance Criteria and Reported Device Performance

Study Information

1. Sample size used for the test set and the data provenance:
   The document does not explicitly state the sample size for the test set. It mentions comparison "to RADIAS" and "To Beutler" for concordance, implying samples were tested on existing methods. The data provenance (country of origin, retrospective/prospective) is not specified.

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. The "ground truth" seems to be established by comparison to existing methods (RADIAS Assay and Beutler method), rather than through expert consensus on a test set.

3. Adjudication method (e.g., 2+1, 3+1, none) for the test set:
   Not applicable, as the ground truth was established by comparison to existing methods, not by human adjudication of independent readings.

4. 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 in vitro diagnostic device for measuring enzyme activity, not an AI-powered image analysis or diagnostic aid for human readers.

5. If a standalone (i.e., algorithm only without human-in-the-loop performance) was done:
   Yes, this is a standalone device ("algorithm only") as it is an in vitro diagnostic assay that directly measures GALT activity. Its performance is reported in laboratory-centric metrics (sensitivity, precision, concordance) without human interpretation as part of the core measurement.

6. The type of ground truth used (expert consensus, pathology, outcomes data, etc.):
   For concordance, the ground truth was established by comparison to legally marketed predicate devices/methods: the RADIAS GALT Assay (K961432) and the Beutler method. For analytical sensitivity and precision, the ground truth is based on the inherent analytical capabilities of the method, likely determined against known controls or reference materials.

7. The sample size for the training set:
   Not applicable. This is an in vitro diagnostic assay based on chemical reactions, not a machine learning or AI model that requires a training set.

8. How the ground truth for the training set was established:
   Not applicable, as there is no training set for this type of device.

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