Actualization of knowledge about the state of measurement of 25-hydroxyvitamin D in serum. A mini-review 2015 - 2016
Abstract
Objective: Actualization of statement in 25-hydroxyvitamin D measurement Method: Information from websites and other documents of international vitamin D standardization program VDSP and from recent publications deals with 25-hydroxyvitamin D measurements in human serum Results: After 1 year we can see that effect of international standardization program VDSP is negligible both in precision and bias values. Significantly higher problems with analytical quality show immunochemical methods than separate measurements.
Standardization process VDSP continues in 2015-2016 by study of the commutability experiments.Their target is to create highly commutable control materials for CAP and DEQAS programs, assured reliable verification of standardization level in routine and research clinical laboratories. Many recent publications are devoted to assessment of components, negatively influenced the results of 25-hydroxyvitamin D measurements in serum samples.
Objects of interest are namely 25-hydroxyvitamin D2 and its level of cross immunoreaction, influence on bias level by 24, 25-dihydroxyvitamin D content, problems with 3-epi-25-hydroxyvitamin D3, and also with vitamin D bound protein (VDSP). These influences, resulted to elevated bias values are much more frequented in immunochemical methods than in separate methods and are in different immunochemical methods very different.
Discussion: Risk of increased bias values namely in immunochemical methods can decreased reliability of classification of deficiency by vitamin D in individual patients. It also can be the source of problems in analysis of children due to high concentration of 3-epi-25-hydroxyvitamin D3 and in analysis of dialyzed patients due to problems with VDBP.