MZ reviewed the literature, wrote the manuscript and revised the article. of 33.25??10.09?years were mainly composed of males (94.8?%). The seroprevalance rate was 4.9?% for Anti-HBc and 31.9?% for HBsAb. The majority (58.6?%) of Anti-HBc positive cases were regular blood donors with 42C49 TAS 103 2HCl years being the largest age group (41.4?%). Neither individual NAT nor pooled NAT test detected any HBV DNA. Conclusion However, Screening of anti-HBc Ab is usually proposed as a method to identify previous contact with HBV, but there is controversy in literature data regarding the cost-benefit of exclusion of positive anti-HBc Ab in blood donors. Our data does not suggest HBc-Ab test as a screening tool in the study setting. strong class=”kwd-title” Keywords: Hepatitis B virus, Blood Transfusion, Blood Donors, Occult hepatitis B virus, Blood safety Background Blood and blood products are inseparable part of the treatment in many medical settings. Therefore, the availability of adequate safe blood and blood products remains a major concern in health care system and transfusion practice. The limited data from WHO Global Database on blood safety indicates around 92 million blood donations worldwide and more than 9 million blood transfusions in ninety countries, annually [1]. Currently, Iran has achieved 100?% voluntary non-remunerated blood donation, and in 2011 about 2 million blood donations were recorded [2]. For a variety of the most important infectious brokers that are transmitted TAS 103 2HCl via blood transfusion such as HBV, HCV, HIV and syphilis, screening assessments are performed as routine practice. However, despite considerable improvements in eligibility criteria for blood donation WASF1 and development of more advanced screening methods, transfusion transmitted infectious brokers like hepatitis B virus still present as a threat for blood safety. Currently About 0.2?% TAS 103 2HCl of donated blood from apparently healthy donors in Iran is usually diagnosed as HBsAg-positive and is hence discarded [2]. This phenomenon is usually observed on different scales in other blood services across the world [3]. By perceiving the HBV host interaction, it was shown that even HBsAg negative individuals might be infected and there is a chance TAS 103 2HCl of transmission especially upon transfusion. Thus, despite all efforts including the use of a highly sensitive HBsAg test, transmission may still occur from apparently healthy blood donors. This may be attributed to the inability of the screening assessments to detect HBsAg during a window period or as a result of the occult HBV infections (OBIs). OBI arises when the HBV DNA is usually detected, while HBsAg remaining undetectable. In about 20?% of cases the only positive marker is usually HBV DNA but in other situations anti-HBc or anti-HBs could be detected as well. Several factors may be involved in OBI, including mutated HBsAg, low level expression of HBsAg or entrapment of antigen in the circulatory immune complexes [4C6]. The prevalence of hepatitis B virus infection in the population and the sensitivity of laboratory methods could affect the reported prevalence rates of OBI [7]. Some studies have suggested that in HBsAg unfavorable and anti-HBc positive cases, there is a possibility of low level infectious HBV viremia. This study was conducted in order to determine the frequency of anti-HBc and HBV DNA in blood donors with undetectable HBsAg. Since HBsAg test is the only screening method in Iranian blood donation centres, the necessity for supplemantary screening assessments such as anti-HBc or NAT test were studied as well. Methods During the time frame of the present study (2013), 86,182 blood donations from voluntary blood donors in two main blood collection centres (Kermanshah and Ahwaz) were evaluated for HBsAg. HBsAg positive donors were excluded and HBsAg adverse donors were considered for inclusion in the scholarly research. The donors had been classified as first-time,.