Objective: To test the performance of direct chemiluminescence immunoassay(CLIA) in the determination of serum 25-hydroxyvitamin D [25(OH)D] concentration.
Methods: The CLIA analyzer of Italy DiaSorin was used to measure the 25(OH)D concentrations in the Standard Reference Material 972 a of National Institute of Standards and Technology, DiaSorin control materials, blind samples of Vitamin D External Quality Assessment Scheme(DEAQS), and outpatient serum samples. The functional sensitivity, precision, accuracy, recovery, and linearity were evaluated, and the samples of mild hemolysis, 5 days' storage at 4 ₿ and >1 year's storage at-80 ₿were tested for 25(OH)D.
Results: The functional sensitivity was<4 ng/mL. The coefficient of variations of intra-and inter batch were<8. 1%. The relative deviation was-3. 1%-5. 7%. The recovery rates were 82. 8%-112. 9% and it had good linearity in the range of 7. 6-128. 1 ng/mL. Compared with fresh serum, the serum 25(OH)D concentration was not affected by mild hemolysis or being stored at 4 ₿for 5 days, but averagely decreased at 7. 6% by being stored at-80 ₿for more than 1 year. Compared with others, the deviation was-2. 9%-3. 6%. The differences in precision, accuracy and recovery of this method among the three different hospitals is slightly.
Conclusion: The performance of direct CLIA for 25(OH)D assay meet the basic technical requirements for laboratory medicine, and is laborsaving and timesaving.
Keywords: 25-hydroxyvitamin D; direct chemiluminescence immunoassay; performance variation; serum detection.