Objective: This study was aimed to retrospectively evaluate HIV, HBV, HCV and syphilis test results of 204 000 blood donors between 2000-2011 and also to compare the optic density (OD) values obtained by HIV ELISA with the confirmatory test results.

Materials and Methods: HBsAg, anti-HCV and anti-HIV½ screening tests were performed with enzyme immuno assay (EIA) tests using IMx between 2000-2002, AxSYM between 2002-2006 and ARCHITECT system (Abbott Laboratories, Chicago, IL, USA) between 2007-2011. Syphilis screening was done by Venereal Disease Research Laboratory (VDRL) test between 2000-2003, by test strips (Determine TP; Abbott Laboratories, Chicago, IL) between 2003-2007 and by ARCHITECT system (Abbott Laboratories, Chicago, IL, USA) between 2007-2011. The confirmation of anti-HIV½ results was done by Western Blot.

Results: Among the total of 240.000 consecutive blood donors, the overall seroprevalences of HBV, HCV, HIV½ and syphilis were 3.14, 0.92, 1.06, and 2.33%, respectively. However, the results of HIV confirmatory testing revealed the seroprevalence as 0.002%. It was detected that for HIV½ only the samples with OD>10 were confirmed to be positive by the Western Blot test.

Conclusion: Validation of optical density values obtained by ELISA tests used for blood screening is an important issue especially in screening of blood donor samples. However, it is still an obligation to confirm all positive ELISA HIV½ samples by a Western Blot test.