2.2 Data/sample collection and laboratory procedure
A structured questionnaire was used to collect demographic data such as age, gender, place of residence, level of education completed, occupation, and marital status. An estimated volume of 5 mL of blood sample was collected from all participants and placed in tubes containing ethylenediamine tetraacetic acid (EDTA) for serological (HBsAg) and biochemical (AST and ALT) screening. Additional screening for other sexually transmitted diseases was performed, to rule out HCV, HIV, and syphilis infections. For this study, donors with a negative result for HBsAg were considered the control group, while the group with a positive result for HBsAg was considered the test group. All the serological screening was performed with the ARCHITECT PLUS i2000SR immunoassay analyzer (ARCHITECT, Abbott Laboratories) using the HBsAg QUAL II detection kit (Abbott Laboratories, Ltd.) to screen for the current presence of HBsAg, while the biochemical screening was performed with the automatic biochemical analyzer Cobas C111 (Roche), using the AST (Roche, Germany) and ALT (Roche, Germany) detection kits, for evaluation of possible liver damage resulting from HBV infection. Positive and negative controls were added during all laboratory procedures following the manufacturer’s instructions. All laboratory processing as well as the interpretation of the results were carried out according to the manufacturer’s instructions. Patients reactive to the HBsAg biomarker were classified as positive for HBV infection. For purposes of this study, the reference range for AST was considered to be 8-48 U/L while for ALT it was 7-55 U/L. Furthermore, AST/ALT ratios less than one were assigned to donors with acute or non-alcoholic liver disease, while an AST/ALT ratio greater than or equal to 1, was assigned to donors with suspected chronic liver disease, viral hepatitis, or liver toxicity.