Hello Dr., I had the hepatitis surface antigen test (chemiluminescent microparticles immunoassay) blood test at the end of 85 days post oral sex exposure(fellotia) and the test was negative. Do i need to retest for any confirmation. In reports it is mentioned false negative can be due to presence of mutant forms of HbsAg. Is it a worrying factor for any retest, if it is then which Hepititis B test to be done. I did HbsAg rapid screening(method: immunochromatogratography) at 3 weeks after exposure and it was also negative. Please guide me..