At this point there is no reason for you to worry further. EWH
Welcome to the Forum. The chances that your partner gave you HIV are very, very low if she had a negative test 3 days after your encounter. Persons who have HIV and are able to transmit it to others typically have positive tests or their tests become positive within a week or two following the encounter. The quickest and most direct way to address your question, if she'll do it, is for your co-worker to get tested again at about 2 weeks following the encounter. If she is negative at that time, then there is no risk.
As for your own testing, standard antibody tests are 100% conclusive in situations such as yours at 8 weeks following an exposure.
As I said, the likelihood that you acquired HIV through this single encounter are truly miniscule. I would not be worried if I were you. I hope my comments provide some direction. EWH
My co-worked re-tested negative at day 16.
Dr, so it's a scientific impossibility for her to have passed HIV to me given this test result?
Thanks for the help.