Testing after a rape

[jenn8283]

I was raped six weeks ago. A man broke into my house and raped me while I was sleeping. I woke to him yell profane words at me and told me he gave me hiv. I took a six week hiv test today. Two weeks after the rape I was not sure if he came back and raped me again b/c my clothes were on a little different and I had a lot of wetness.

My question is the six week test conclusive even if i might have been violated two weeks after the first incodent?

[jeremy_0808]

Hello doctor
I'm not sure I understood your statement.
If I had high risk situation (sex with HIV+ person)- do I need the 3 months test (because 6 weeks won't be 100%)?
Again, thank you very much.

[t_from_bayarea]

I would certainly recommend a 12-13 week HIV test to be absolutely sure. Since you are so riddled with uncertainty as to "if you were" assaulted a second time. I have known someone who was slipped HGH in her drink at a nightclub and woke up on the sidewalk. Of course she didnt know what the heck happened but she knew something wasnt right. She went to the doctor who checked her and confirmed that she indeed was raped. So to the poster above, you can be assaulted without knowing it. Either by being injested or injected with a date rape drug.

Good luck to you and take care.

[shygirl1981]

I don't think the doctor can be any more thorough than he already has been.

[H. Hunter Handsfield, M.D.]

As I said originally, "a test 6 weeks after the last exposure is close to 100% certain. However, after sexual assault, most authorities recommend a final test 3 months after the event."  So the final testing time is up to you.

HHH, MD

[jenn8283]

What I meant to say in my last post is would my test I took yester day six weeks possibly four week test be conclusive/accurate? I don't want to take a three month test unless it is absolutely necessary.

[H. Hunter Handsfield, M.D.]

OK, here it is again (for at least the 10th time).  

Assume a low risk exposure, like a typical heterosexual exposure with a partner of unknown (but probably negative) HIV status.  Say the odds someone acquired HIV were 1 chance in 100,000.  Now assume a test is 95% accurate at 4 weeks and 99.9% accurate at 3 months.  After a negative test at 4 weeks, the odds the person has HIV (despite the test result) is 0.00001 x 0.05 = 0.0000005.  That's 5 in 10 million, or once chance in 2 million.  That's so low to be considered zero.  (It's 75 time LESS than the lifetime chance of someone living in the US being killed by a lightning strike!)

Now assume a very high risk exposure, like a gay man who has unprotected anal sex with a known-infected partner (or being raped by an infected man).  The odds of infection might be 1%, i.e. 1 in 100.  Test negative at 4 weeks.  The odds the person has HIV despite the negative test are 0.01 x 0.05 - 0.0005.  That's 1 chance in 2000.  Pretty low, and the test result is reassuring.  But not nearly reassuring enough; most people will not accept a 1 in 2000 risk of being infected an not knowing it.  Therefore, that person needs another test at 3 months.  At that time, a negative test result translates into 0.01 x 0.001 = 0.00001, 1 chance in 100,000.

Same test, but the differenence in circumstances leads to different levels of reassurance.  The bottom line is that the higher the risk, the more important it is to carry out testing to a later time, such as 8 weeks or even 3 months.  The lower the risk, the less it matters to wait that long.

Only you can decide whether you "need" testing as long as 3 months after exposure.  But for most people, a single test at 4-6 weeks is sufficient.  (If you're going to worry about the possibility of HIV despite a risk of less than 1 in a million, I have to assume you never drive, don't cross busy streets, and never take commercial flights--all of which have a much higher chance of killing you.)

HHH, MD