I was with a prostitute.
With a latex glove I have put a finger in the bum of the lady, about 1 minute in and out.
Then I pulled out the latex glove. The lady then made the same with me.

Well unfortunately I do not know if the lady has used the same glove put in my ass as I for her.
Would that be a risk for HIV?
If the lady me stuck the same glove and the same finger in the butt as I for her previously ???

after which time is excluded with a 4.Generationstest in the usa an HIV infection?

How secure is an HIV PCR test 16 days after risk?

Welcome to the forum- the rectal masturbation you describe is a low risk event and should not put you at risk for HIV or any other STI.  There is little chance that she used the same glove on you as you used on her (they are fragile and rarely withstand being taken on and off without breaking) and even if she did, this would still constitute safe sex..  STIs (including HIV) are not effectively transmitted through the two step process in which the virus (or bacteria) gets onto one person's finger and then is transferred to a sexual partner on the contaminated finger.  I would not be concerned and see no reason for SI or HIV testing of any sort

With regard to your other questions- 4th generation HIV test results provide conclusive results at any time more than 28 days (4 weeks) after an exposure.  At that time test results become completely reliable.

Despite what the manufacturers and those marketing them claim,. and HIV PCR at 16 days after exposure, while strong evidence that a person is not infected, is not recommended for this purpose and there are few high quality data evaluating this sort of test for this purpose. 

I hope this information is helpful to you.  EWH

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