Referenced Quotes about HIV/AIDS Tests and Measurements

Antibody Tests (ELISA, Western Blot)

Antibody tests are the most commonly performed. Usually an ELISA test is performed, and then repeated if positive. Following that, for positive ELISAs only, a Western Blot (WB) is performed. ELISA is not a Yes/No test, it is only a continuum of color change that is interpreted in this way because of an arbitrary cutoff point. Western Blot has the purported HIV proteins separated on a strip, with various methods used for interpretation (varying from country to country, and from organization to organization). Both types of tests measure antibodies, which in many diseases are considered a sign of immunity (particularly in the absence of symptoms). Why are antibody tests considered a sign of fatal disease in HIV/AIDS? Why are two of the same type of test used to validate each other?