Hi Doc, I was looking at a couple of HIV related websites when I found a statement made by Dr. Josh Bamberger of the San Francisco PEP Feasibility Study. He said:

A 3rd generation anitbody (ELISA) test should be as sensitive and specific as a viral load test three months after exposure. I would not recommend a viral load test in this setting as it does not improve accuracy and the 5-10% false positive rate is unacceptable.

This statement confuses me a bit. I think he is trying to say that the 3rd generation Elisa would be very accurate 3 months post exposure. But what confuses me is that he mentions that the tests have similar sensitivity and specificity at this point, and then goes on to say that a viral load test is unacceptable with a 5 - 10% false positive rate. Now, logic tells me this would affect the specificity of the test. And if the Elisa has similar specificity, that means the Elisa would also be unacceptable.

Can you shed some light on this if you have some time? It seems like a contradictory statement to me. I am just curious.

Bobby

He is making the argument that by 3 months almost everybody who is infected would be seropositive. Thus an additional test to confirm this adds nothing. He is also referring to their own data as well as published case reports where people who were seronegative after a high risk exposure, were found to have positive plasma HIV RNA tests at low (50-1000/ML) copy number. Subsequent and further diagnostic testing revealed that these folks were HIV negative. MH