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Can you?

Dec 7, 2008

Answer this?

Hi Doc,

I know your stance on testing, i.e. symptoms mean nothing and the only test you need is an Elisa at 3 months.

But, I got an email from the CDC saying that a PCR test is accurate 9-11 days post exposure (this info is also on their website).

From the archives, I gather that a PCR test is not used to detect HIV due to its cost, technical considerations in performing the test, and rate of false positives.

What about rate of false negatives? Have you ever come across any situation where the PCR test was a false negative? Would a PCR test be positive only if symptoms were present (or could it be positive even before ARS symptoms manifested)?

Finally, who do we believe? The CDC says one thing, someone else says another, etc. etc.

Response from Dr. Frascino


The CDC and I do not disagree on this point! False-negative tests with PCR technology are rare, especially compared to false-positive tests. A properly performed PCR can detect HIV infection well before anti-HIV antibodies are detectable in the blood. The "9-11 days post exposure" is not standardized from test to test or from laboratory to laboratory. In spite of this information, I must point out PCR testing is not routinely available around the globe. Due to the rate of false positives, other technical considerations and cost, it is not recommended for routine HIV screening. At this point in time, the most accurate and cost-effective screening remains an HIV-antibody test at the three-month mark. The CDC guidelines and recommendations for routine HIV screening remain unchanged and corroborate my views.

Hope that helps clarify things.

Dr. Bob

Another from the badda bing!
Raltegravir & Side Effects

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