APPLICATION OF A MODIFIED INCSTAR EPO-TRAC 125 RIA FOR MEASUREMENT OFSERUM ERYTHROPOIETIN CONCENTRATION IN ELITE ATHLETES/

Objectives: To evaluate the analytical performance of a radio-immunoas say for measurement of erythropoietin. Design and Methods: The INCSTAR Epo-trac I-125 radioimmunoassay was examined for applications requiri ng sensitivity and precision within the normal range. Results: Sensiti vity was improved by increasing sample volume to 300 mu L. Minimal det ectable concentration was determined at 5.3 U/L, %CV ranged from 4.8-5 .8 and 13.3-6.4 for intra- and inter-assay imprecision, respectively. Accuracy was maximized by controlling for lipemic and hemolyzed sample s and ensuring serum was separated from the clot within 1 h of collect ion. Values demonstrated good correlation to the Diagnostic Systems La boratory RIA-kit. Conclusions: With sample volume increased to 300 mu L and control of sample preparation, the INCSTAR Epo-trac 125/RIA show ed improved precision. Assay sensitivity at lower values allows resolu tion of changes in erythropoietin within the normal reference range. A ge was not found to influence erythropoietin concentration. Within 10 days sojourn at moderate altitude and increase in circulating erythrop oietin and reticulocytosis was observed in swimmers.