Solid-phase Immuno Radio Metric Assay (IRMA) of 25-hydroxy Vitamin D and Displacement from Serum Binding Proteins for Resource-limited Settings

The development of a solid-phase immune radiometric assay to satisfy the pressing need for a simple yet effective method for measuring 25-hydroxyvitamin D[25(OH)D] in a serum and thus more suited to routine use in clinical biochemical laboratories. The aim of this study was not to compare our home made with commercially available method but tested for general assay performance, including homemade polyclonal antibody specificity. Methods: We used our home made radioiodine (125I)-based IRMA kit for the detection of 25(OH)D. 

It is based upon, non-competitive displacement agents which enable effective separation of vitamin D metabolites from binding proteins to enable the amount of vitamin D metabolites to be measured, without competing with the proteins or requiring its solvent extraction from the serum.Our package called: “cgea 25(OH)D-irma” is analytically, all qualities we expect from a good medical test kit, with a precision of coefficients below 13%as well as intra-series that in inter-series and inter-batch accuracy with a linearity estimated at 0.8ng/ml and good stability of the radio labeled trace(60 days). Conclusion: Simplification of the methods for extraction and separation has been a key feature in the improvement of assays for vitamin D in Democratic Republic of Congo.