Why is hiv pcr used to test blood at blood banks, babies and acute hiv symps but not as a diagnosis? other than cost and false positive what could be the reason that some docs don't trust it? thanks

PCR is a ..: ..complex test, & more technically difficult to perform accurately than the antibody tests. Because PCR detects viral-RNA (proteins within the HIV virus) it is positive early in the course of infection & is used to try to confirm/exclude HIV as a diagnosis for a set of symptoms. You are correct that there are more false positives with PCR than with antibody tests. Antibody tests are gold standard