| abstract |
It is described in the present invention that, after the absorbed material has been measured, an immunoabsorption of free 25 (OH) vitamin D from blood or blood components, in particular serum or plasma, is performed. Fluoro-alkyl surfactants are used to enhance the solubility of vitamin D and measure previtamin D. Thus, the present invention applies binding proteins to absorb free 25 (OH) vitamin D. The binding protein comprising 25-OH vitamin D is then subjected to economic binding assays with labeled vitamin D compounds, preferably radiolabels, fluorescent labels, luminescent labels, biotin labels, gold labels or enzyme labels. In addition, immunocaptured 25-OH vitamin D can be quantified by mass spectrometry. |