title: Evaluation of a new radioimmunological assay for the determination of the B subunit of creatine kinase enzyme.
abstract: We used a new radioimmunological (RIA) kit for the assay of B subunit of creatine kinase enzyme (CK). This RIA system uses a specific antisera against the B subunit as ligant, human CK-BB labelled with 125I as tracer, and purified human CK-BB isoenzyme as standard. The mean (+/- SD) sensitivity obtained was 0.25 +/- 0.16 ng/tube and the between assay variability was about 9-10%. Serum levels of 113 normal subjects was not normally distributed. The 95% of values was found below 5 ng/ml. This new RIA is usefull in clinical practice when serum levels of CK-BB isoenzyme must be determined. This method is quickly and it is characterized by a good degree of precision, but the CK-MB isoenzyme cross-reacts for about 40% in this RIA system. Therefore, for the clinical diagnosis by means of this RIA it is necessary to rule out the concomitant elevations of serum CK-MB values.
mesh_terms: D003402:Creatine Kinase / Q000097:blood*; D003429:Cross Reactions; D006801:Humans; D007527:Isoenzymes; D046911:Macromolecular Substances; D011863:Radioimmunoassay / Q000379:methods
chemical_list: D007527:Isoenzymes; D046911:Macromolecular Substances; D003402:Creatine Kinase