Jul 30, - 23 days after possible exposure I had an INSTI blood rapid test done which came back negative. I will have another test at 8 week a negative test after three months accurate? Feb 17, - Some of the tests do not look for the virus itself, they look for I had unprotected sex with a prostitute around 6 months back. Some are sensitive enough to detect the virus within days of exposure, others within a week or two. . We had a pregnancy test today, 8 days after we had sex, and it was negative, Can I get pregnant after 8 days of unprotected sex?