Antibody tests for infections can mislead

This case report just published in AIDS, the Official Journal of the International AIDS Society describes an individual whose infection rapidly progressed to death without ever showing antibodies to HIV on blood tests. This is one reason why we use PCR (DNA amplification by polymerase chain reaction) to quantify ('count') the virus ('viral load') for conditions like AIDS and chronic hepatitis, and the same technology for Lyme Disease. There are a number of factors that can cause the antibodies not to be expressed. As my patients know, this is also why we can't depend on antibody tests to reliably diagnose food allergies.