Quality assurance for immunochemical methods.

Recently developed immunochemical methods offer many advantages, although they may suffer from problems in standardisation due to the difficulties in the characterisation of immunological reagents. The reliability of the results is influenced by the availability of reference materials, calibrators, reagent kits and instruments. Since inter-laboratory quality control programmes have been limited by the lack of standard reference materials, laboratories using immunoassays should, at least, implement an internal quality control programme aimed at avoiding systematic errors, and adhere to the rules for good laboratory practice. The exchange of home-made materials as well as the control over pre-analytical factors (selection, collection and storage of specimens) within collaborative studies could be useful to the harmonisation of the measurement procedures. This paper deals with whether such quality requirements are or can be fulfilled with regard to early markers of nephrotoxic effects based on the immunochemical determination of proteins and kidney-derived antigens in urine or serum.