Objective: Microbiological screening of blood donors for agents of transfusion transmitted infections is important and necessary for ensuring the transfusion safety. The aim of this study was to prepare internal quality control (IQC) sera for HBsAg screening of blood donors by using the human plasma collected from blood donors with detectable HbsAg levels.

Methods: Quarantined fresh plasmas separated from the whole blood samples of donors with repeatedly reactive screening tests for HbsAg with high S/CO ratio (>1000) and detectable (>50IU/ml) HBV DNA were used for the preparation of IQC sera. In vitro coagulation of pooled plasma was performed by using calcium chloride and bovine thrombin. Following the removal of coagulum, dextrane sulphate was added and precipitation of lipids was carried out in a series of centrifugation processes. Samples from the sera pool were diluted with PBS and diluted samples were tested for HbsAg reactivity. Recorded S/CO ratio of IQC samples from each category was applied to Levey-Jennings control charts and evaluated according to Westgard rules.

Results: In descriptive analysis of high, medium and low reactive IQC samples the mean was found to be 3323.75, 1725.57 and 219.57; the median was determined as 3401.76, 1753.48 and 217.34; the standard deviation was calculated as 271.19, 210.62 and 14.93, respectively. Coeffcients of variation for high, medium and low reactive IQC samples were determined as %8.1, %12.2 and %7.6, respectively.

Conclusion: In concordance with ISO15189 standards that suggest the use of independent run controls for immunoassays, it would be beneficial to prepare IQC samples from collected blood in blood banks.