Is a negative rapid hiv antibody test done after 90 days of last exposure conclusive?if i had possible hep c coinfection should i retest at 6 months?can i test hep c now(120 days of last exposure) to get a conclusive result?

False negative result may occur with rapid HIV antibody test. The most accurate test will be fourth generation HIV test. Yes, for ruling out Hep C infection you should be retested at 6 months post exposure. By UPTODATE: ELISA tests for detecting anti-HCV antibodies become positive as early as eight weeks after exposure, with most patients seroconverting between two and six months after exposure.