Introduction: Brucellosis is a major zoonosis in the developing countries including India. The reported incidence of human brucellosis in endemic areas varies widely, from <0.01 to >200 per lakh population. Despite being endemic in many developing countries, brucellosis remains underdiagnosed and underreported. Interpretation of the serological tests is often difficult in endemic areas due to presence of antibodies against Brucella in high proportion of the population . Hence estimation of normal baseline titers of Brucella agglutinins in healthy individuals residing in endemic areas and the cutoff values are necessary for the serodiagnosis of brucellosis. AIM: To determine the baseline titre of brucella agglutinins, amongst apparently healthy blood donors in Dhule, Maharashtra, India. Materials and Methods: A total of 480 serum samples were analyzed by RBPT and STAT method for detection of Brucella Agglutinins over period of 6 months from July 2016 to December 2016. These agglutination tests were performed according to manufacturer‘s guidelines by using commercial kits containing stained Brucella abortus Antigen suspension. Result: Of these 480 samples 32 (6.7%) were positive for Brucella agglutinins by RBPT. Of these 32 RBPT positive samples 22(4.6%) showed agglutination by STAT. Amongst 22 STAT positive samples 15 samples were found positive for Brucella agglutinins at 1:40 and 7 samples were positive at 1:80. Conclusion: As RBPT is very sensitive test and its results should be confirmed by STAT. Since the base line titre of 1:80 by STAT was demonstrated in healthy individuals, titres 1:160 and above should be considered significant along with consistent clinical features.

Keywords: Brucellosis; Baseline Titre; RBPT; STAT; Agglutinins.