Occult HBV infection in hemodialysis patients in Qazvin

Hbs-Ag positivity rates in dialysis patients correlate with endemicity in the general population. There is a subset of patients with occult HBV infection that defined as the presence of detectable HBV-DNA by PCR in patients who are negative for Hbs-Ag. We decided to detect the occult HBV cases in our hemodialysis patients. With support of charity society of renal patients of Qazvin, a cross sectional study was scheduled. We tested all the 134 hemodialysis patients in Buali Hospital of Qazvin university of medical sciences for viral hepatitis B in 1 year period. All the patients were chronic hemodialysis patients. Then Hbc-Ab and Hbs-Ag were detected by ELISA tests. Duplication is considered to have true test results. After completion of this stage, the aliquoted samples were tested for qualitative HBV-DNA (PCR). The positive cases for HBV-DNA were tested again in a referral center to ensure of test results. 43% were female and 57% were male cases. We had 5 positive cases for hepatitis B by ELISA tests (3.7%) that 4 of them were Hbc-Ab and HBV-DNA positive also as expected, although 1 of them had negative test result by PCR test unusually. We detected 4 (3%) another positive PCR test results for HBV that had negative tests for Hbs-Ag, called occult HBV cases. 3 (75%) of these occult cases were Hbc-Ab negative and known as seronegative occult cases. No significant association was found with the duration of hemodialysis, age or sex and HCV positivity in these cases.Age of occult HBV cases was significantly more (P=0.02). As mentioned most of our occult HBV cases were seronegative. It seems that Hbc-Ab detection is not sensitive test in these cases. Segregation of positive HBV cases in hemodialysis units is mandatory and new protocols may be considered to detect the cases for segregation in the future.