Ligand trap useful in immunoassays of biotin or free biotin containing samples and improved immunoassays using these ligand traps

摘要

The present invention provides a process for the detection of analytes in body fluids containing free biotin by immunoassay with the use of biotin conjugates for the labelling, immobilization or complexing of immunological reagents, wherein the biotin present in free form is removed from the immunological reaction by incubating the sample solution with polymer particles consisting of a core and a covering which, as core, contain a polymer which has a plurality of binding sites for biotin and, as covering, at least one layer of protein, peptide, carbohydrate or co- polymer of carbohydrate and amino acids, the layer thickness of the covering being so adjusted that the coating is permeable for the free biotin but not for the biotin conjugate.