Chemistry Analyzers for Diazyme's 25-OH Vitamin D Assay for Clinical Chemistry Assay include those listed below but are not limited to:
Alfa Wassermann |
Siemens |
Horiba |
ThermoFisher |
Roche |
Mindray |
*Parameters Proposed
Diazyme's 25-OH Vitamin D Assay for Clinical Chemistry Analyzers
Data sheet Brochure Published Paper
Assay Principle:
Diazyme's Enzyme-Immunoassay FemtoQuant™ 25-Hydroxy Vitamin D test 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, an anti-Vitamin D antibody 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. A nitrophenyl-ß- galactoside derivative (NPG) is used as the enzyme substrate. The reaction's product has maximum absorbance at 415 nm. The 25-OH Vitamin D concentration of a sample is proportional to the measured β-galactosidase activity.
Diazyme 25-OH Vitamin D for Clinical Chemistry Analyzers Kit Configuration:
Diazyme's Vitamin D assay kit contains 1 sample diluent and 3 liquid stable reagents and calibrator set. The intended use is for the quantitative determination of 25-(OH) D levels in serum or plasma, on automated chemistry analyzers, and for the assessment of Vitamin D sufficiency.
Assay Features:
- Multiple instrument options available
- Reagent kit, calibrator and control sets offered separately
- Liquid Stable format
- Minimal sample of only 20 μL needed
- 15-19 minutes to first result
- Report total 25-OH Vitamin D (D2+D3)
- No off-line sample pretreatment needed
- Excellent Correlations to LC-MS/MS and leading 25-OH Vitamin D Immunoassays
- Cost effective
Assay Procedure:
The assay procedure for the Roche Modular P chemistry analyzer is shown below: Specimen calibrator, control and samples are first diluted onboard: 20 μL of serum which is then diluted with 155 μL of diluent. Once diluted an additional 20 μL of the diluted specimen is then used for analysis.
Assay Accuracy:
The performance of this assay was compared to the performance of a legally marketed 25-OH Vitamin D enzyme immunoassay. The results for 98 serum samples are shown in the table below:
Deming Regression Analysis | 95% Confidence Interval |
Slope | 1.005 (0.969 to 1.041) |
Intercept | -0.21 (-2.15 to 1.73) |
Correlation Coefficient | 0.984 (0.976 to 0.989) |
Range | 9.5-140.9 |
Assay Linearity:
Eleven levels of linearity were prepared by diluting a high serum sample with Vita-min D-depleted serum. Linearity levels were prepared according to the CLSI EP6-A guideline. Measurements were done in triplicates. The assay was found to be linear between 7.6 and 147.8 ng/mL.
The assay demonstrated excellent correlations with results determined by LC-MS/MS and DiaSorin CLIA methods with R2 values of >0.95 and 0.96.
Assay Sensitivity:
The LOB, LOD, and LOQ of Diazyme's 25-OH Vitamin D Assay for Clinical Chemistry were determined according to CLSI (formerly NCCLS) EP17-A guidelines. The assay's LOB = 2.0 ng/mL; LOD = 3.5 ng/mL; and LOQ = 7.6 ng/mL.