Tehran University of Medical Sciences Iranian Journal of Microbiology 2008-3289 12 5 2020 10 31 475 482 Muslim Musa Department of Community Health, Al-Nasiriyah Technical Institute/Southern Technical University, Al-Nasiriyah, Thi-Qar, Iraq Hekmat Ateya Department of Microbiology, School of Veterinary Medicine, Thi-Qar University, Al-Nasiriyah, Thi-Qar, Iraq 2020 02 05 2020 09 03 Background and Objectives: The prevalence of Hepatitis B virus (HBV) infection among haemodialysis (HD) patients has been well documented. In addition to overt infection, occult Hepatitis B infection exists in which a patient who is diagnosed seronegative for Hepatitis B surface antigen (HBsAg) shows positive HBV-DNA on using more accurate molecular methods. This study aims to determine the prevalence of overt and occult HBV infection among the HD patients who had attended Al-Nasiriyah dialysis centre during a two-month period. Materials and Methods: Serological qualitative detection of HBsAg by rapid test (strips), enzyme immunoassay (EIA, HBsAg) and molecular (real-time polymerase chain reaction (real-time PCR)) was conducted for quantitative detection of HBV in HD patients’ serum. Results: The prevalence of overt HBV infection among HD patients was 3.7%. The viral load of HBV positive patients was ranging from 5.85 × 101 to 2.16 × 106 copies/ml of serum with median (7.4 × 105 copies/ml). Occult Hepatitis B was not detected in any of the seronegative HD patients (0%). Overt infection was found more in males (80%) than females (20%) (P<0.05). Similarly, infection was found to be higher among patients who had blood transfusions (80%) than those who had not (20%) with statistical significant p<0.05. Although not statistically significant, the mean duration of HD was higher among HBV positive HD patients (17.6) than HBV negative HD patients (14.3). A dual infection of HBV and HCV was not detected in this study. Conclusion: Nosocomial transmissions at HD centres and blood transfusion are important risk factors. Besides serological screening, real-time PCR offers a safeguard against the spread of overt and occult HBV infection and determines the viral load of the positive patients. https://ijm.tums.ac.ir/index.php/ijm/article/view/2475 https://ijm.tums.ac.ir/index.php/ijm/article/download/2475/1284