(166 days)
The ARK Methotrexate II Assay is a homogeneous enzyme immunoassay intended for the quantitative determination of methotrexate in human serum or plasma on automated clinical chemistry analyzers. The measurements obtained are used in monitoring levels of methotrexate to help ensure appropriate therapy. Specimens from patients who have received glucarpidase (carboxypeptidase G2) as a high dose methotrexate rescue therapy should not be tested with the ARK Methotrexate II Assay.
The ARK Methotrexate II Assay is a homogeneous immunoassay based on competition between drug in the specimen and methotrexate labeled with the recombinant enzyme glucose-6phosphate dehydrogenase (rG6PDH) for binding to the antibody reagent. As the latter binds antibody, enzyme activity decreases. In the presence of drug from the specimen, enzyme activity increases and is directly related to the drug concentration. Active enzyme converts the coenzyme nicotinamide adenine dinucleotide (NAD) to NADH that is measured spectrophotometrically as a rate of change in absorbance. Endogenous serum G6PDH does not interfere with the results because the coenyzme NAD functions only with the bacterial enzyme (rG6PDH) used in the assay. The ARK Methotrexate II Assay consists of reagents R1 anti-methotrexate monoclonal antibody with substrate and R2 methotrexate labeled with recombinant G6PDH enzyme. The test system includes the ARK Methotrexate II Calibrator, ARK Methotrexate II Control, and ARK Methotrexate II Dilution Buffer.
The ARK Methotrexate II Assay is a homogeneous enzyme immunoassay for the quantitative determination of methotrexate in human serum or plasma.
Here's an analysis of the acceptance criteria and the study proving the device meets them:
1. Table of Acceptance Criteria and Reported Device Performance:
| Acceptance Criteria | Device Performance (Reported) |
|---|---|
| Limit of Quantitation (LoQ) | Established as 0.030 umol/L. Acceptable inter-assay precision ( |
N/A