25-Hydroxy Vitamin D
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Product Features
The assay uses a Vitamin D binding protein which binds Vitamin D3 and D2 at the same affinity. Therefore, the Diazyme assay measures true total Vitamin D (25-hydroxy vitamin D3 + 25-hydroxy Vitamin D2). The assay is linear from 5.9 to 120.2 ng/mL, and has a good correlation with antibody based assays with r2 >0.93 and slope of 0.97. The assay has intra and total precisions of < 10%. Diazyme's 25-OH Vitamin D assay can be run on both a 96-well microtiter plate with a microplate reader.

Assay Principle
The assay is based on the principle of α-complementation of the enzyme β-galactosidase and the competition between an enzyme donor-25-OH Vitamin D conjugate, Vitamin D binding protein and the 25-OH Vitamin D content of a serum sample. Samples with higher 25-OH Vitamin D concentrations produce higher β-galactosidase activities and vice versa. Chlorophenol red-β-D-galactopyranoside (CPRG) is used as the enzyme substrate and the accumulation of the reaction's product (chlorophenol red) is monitored at 560 nm. The 25-OH Vitamin D concentration of a patient sample is proportional to the measured β-galactosidase activity. The assay consists of a sample extraction step during which Vitamin D is irreversibly dissociated from its serum transporter. Extracted samples are then analyzed on a microplate reader after the sequential addition of three reagents. Unlike most microplate-based assays, the Diazyme assay does not require tedious washing steps between reagents. The whole assay procedure takes about 2.5 hours.

  DZ688A-K
Intended use
The Diazyme 25-hydroxy Vitamin D enzymatic assay is designed for the quantification of total 25-hydroxy Vitamin D in human serum and plasma. Assay results are to be used in parallel with other clinical data to assess the Vitamin D status of a patient.
Product Catalog Number Packaging Method/Format
Kit (96 Tests) DZ688A-K

R1: 1 x 8 mL, R2: 1 x 7.5 mL, R3: 1 x 12 mL
Extraction: 1 x 30 mL,
Stop: 1 x 8 mL
Cal: 6 x 1 mL

 Colorimetric, endpoint
Lyophilized powder
Control DZ688A-Con 2 x 1 mL (2 levels)