I had unprotected sex with a girl hiv status unknown but after 10 days she tested hiv negative, might it be undetected hiv and can be transferred thx?

Be Calm: Being negative for HIV 10 days after having sex with you, chances are she wasnt HIV positive at the time of intercourse, although technically the incubation period from acquiring the infection to become positive can be upto 4 wks, depending upon other health conditions. But before you ask her to get tested again in 2 weeks, document your status now and get retested with her in 4-6 wks. Good luck.