Processing reagent and use thereof in assays for detection of analytes associated with a binding protein

Abstract

Methods for preparing a sample for detection of an analyte of interest that is bound in vivo to a protein are provided. The method comprises providing a processing reagent comprising metaperiodate and contacting a sample suspected of comprising an analyte of interest associated with a protein with the processing reagent to form a mixture. The analyte of interest, if present in the sample (or mixture), is separated from its associated protein for detection of the analyte of interest. In one embodiment, the method is applied to samples for the detection of levels of vitamin D circulating in the blood. Samples are processed using the reagent disclosed herein to separate the analyte of interest, vitamin D or a metabolite thereof, from the vitamin D binding protein and/or albumin, for detection of the analyte separated from its binding protein(s).

What is claimed is: 
     
         1 . A method for preparing a sample suspected of comprising vitamin D or a metabolite of vitamin D for analysis, comprising:
 providing a processing reagent comprising between about 0.2 M to about 0.45 M metaperiodate; and   contacting a sample suspected of comprising suspected of comprising vitamin D or a metabolite of vitamin D each associated with a protein with the processing reagent at a ratio of between about 1:2 and 1:12 to form a mixture;   whereby vitamin D or a metabolite of vitamin D, if present, is separated from its associated protein.   
     
     
         2 . The method of  claim 1 , further comprising contacting the sample with a catalyst. 
     
     
         3 . The method of  claim 2 , wherein the catalyst is a metal salt. 
     
     
         4 . The method of  claim 3 , wherein the sample is contacted with the metal salt in the providing step by providing a processing reagent comprising the metaperiodate and the metal salt. 
     
     
         5 . The method of  claim 3 , wherein the mixture is contacted with a solution comprising the metal salt. 
     
     
         6 . The method of  claim 1 , wherein providing comprises providing a processing reagent comprising metaperiodate in the form of a metaperiodate anion associated with a cation of sodium. 
     
     
         7 . The method of  claim 1 , wherein providing comprises providing a processing reagent comprising metaperiodate in the form of a metaperiodate anion associated with a cation of sodium and a manganese salt. 
     
     
         8 . The method of  claim 1 , wherein the sample is selected from the group consisting of whole blood, plasma and serum. 
     
     
         9 . A kit for processing a sample for detection of vitamin D or a metabolite of vitamin D from vitamin D binding protein, comprising:
 one of
 (i) a container comprising a solution comprising sodium metaperiodate and manganese chloride; or 
 (ii) a first container comprising a solution comprising sodium metaperiodate and a second container comprising manganese chloride; and 
   instructions for use.