Background. Screening for HLA-specific antibodies has been performed by complement-dependent lymphocytotoxicity for many years. In recent years, methods involving the use of flow cytometry have been developed. Methods. Panel-reactive antibody (PRA) testing was performed with 20 sera from 20 patients. The patient population consisted of individuals awaiting renal transplantation. PRA evaluations were performed using complement dependent lymphocytotoxicity (CDC) and flow cytometry. Results. The PRA activity in the 20 patients; by CDC, PRA of 7 patients (35%) was negative and PRA of 13 patients (65%) was positive. By flow cytometry, PRA of 5 patients (25%) was negative and PRA of 15 patients (75%) was positive. Results of the two methods were concordant for 12 patients (60%) and discordant results occurred with 8 patients (40%). There is a significant difference was found between the two methods (P > 0.05), this was principally due to the detection of both HLA class I and II antibodies by flow cytometry, whereas CDC detects only class I antibodies. Conclusions. Flow cytometry is the most sensitive technique for the detection of HLA antibodies.