Human Antibodies 20 (2011) 77–82 77 DOI 10.3233/HAB-2011-0242 IOS Press Isolated anti-HBc-IgM antibody among blood donors in the semi-arid region of Nigeria Zaccheaus A. Jeremiah a,∗ , Halima Idris b , Babajide B. Ajayi c , Anthony C.U. Ezimah b , Mohammed B. Malah b and Maryceline M. Baba d a Haematology and Blood Transfusion Science Unit, Department of Medical Laboratory Sciences, College of Health Sciences, Niger Delta University, Wilberforce Island, Nigeria b Department of Haematology and Blood Transfusion, University of Maiduguri Teaching Hospital, Maiduguri, Nigeria c Department of Immunology, University of Maiduguri Teaching Hospital, Maiduguri, Nigeria d Department of Medical Laboratory Science, College of Medical Sciences, University of Maiduguri, Maiduguri, Nigeria Abstract. Laboratory screening for the diagnosis of hepatitis B virus (HBV) infection in blood donors currently consists of testing for hepatitis B surface (HBsAg) antigen alone. The prevalence of isolated anti-HBc-IgM is not yet known in the semi arid region of Nigeria. The major objective of this study was to determine the sero-prevalence of antibody to hepatitis B core antigen (anti-HBc-IgM) and other infectious agent markers; HBsAg, HCV, HIV and Syphilis among blood donors in the North Eastern region of Nigeria. In a cross sectional study from October 2010 to January 2011, 266 blood donors were tested for the infectious disease markers using standard ELISA procedures as contained in the manufacturer’s standard operating procedures. The prevalence of various infectious markers obtained were as follows: HBsAg (8.6%); anti-HCV (1.5%); HIV (2.6%) and anti-HBc-IgM(18.4%). There was a zero percent prevalence of Syphilis in this donor population. The proportion of isolated anti- HBc-IgM antibody obtained was 18.1%. Performance indices for HBsAg were as follows: Sensitivity (10.2%), specificity (91.7%), positive predictive value (PPV) (21.7%), Negative predictive value (81.9%), and efficiency (76.7%). The prevalence of anti-HBc- IgM antibody was higher among first time blood donors (21.4%), and in some ethnic groups. There is a high prevalence of isolated anti-HBc-IgM antibody among blood donors in Maiduguri. The sensitivity of HBsAg was found to be very low and as such many recent HBV infections may be missed during pre-transfusion screening. The use of anti-HBc-IgM screening as a mandatory pre-transfusion screening test is hereby advocated. Keywords: Isolated anti-HBc-IgM, infectious diseases, hepatitis B virus, blood donors, Maiduguri 1. Introduction Laboratory screening for the diagnosis of hepati- tis B virus (HBV) infection in asymptomatic individ- uals such as blood donors generally consist of testing for hepatitis B surface (HBsAg), hepatitis B surface antibody(anti-HBs) and hepatitis B core antibody (anti- HBc) [1,2]. Those who have a positive HBsAg are * Corresponding author: Dr. Z.A. Jeremiah, Department of Med- ical Laboratory Sciences, Faculty of Basic Medical Sciences, Col- lege of Health Sciences, Niger Delta University, Wilberforce Island, Bayelsa State, Nigeria. Tel.: +234 803 404 5636; E-mail: zacjerry@ yahoo.com. usually made to follow-up laboratory testing to define the stage of the hepatitis B infection. The follow-up tests include hepatitis B core IgM antibody (anti-HBc- IgM), Hepatitis B envelope antigen (HBeAg), Hepati- tis B envelope antibody (anti-HBeAg) and hepatitis B virus (HBV) DNA Level [2]. In a setting where HBV infection is acute, HBsAg typically becomes detectable 4 to 8 weeks after infec- tion. Shortly thereafter, IgM anti-HBc appears in the blood. Thus the diagnosis of acute hepatitis B is gener- ally made by the simultaneous detection of HBsAg and IgM anti-HBc [3]. Rarely, acute hepatitis B may be diagnosed during the period when HBsAg titres have declined below detectable levels and anti-HBs have not ISSN 1093-2607/11/$27.50  2011 – IOS Press and the authors. All rights reserved