Q: It is said that ELISA test for detection of HIV/AIDS done after six or nine months does not give 100% true result. After how long should it be done to get a 100% true result? Is it true that ELISA test does not ever give 100% true report and that is why we have to do a Western Blot test?

A:If an ELISA test is done for HIV six months after exposure, and the test result is negative then you can rely on the report as being accurate. Negative tests, done after the window period (3 to 6 months after exposure) are 100% to be relied upon. However a single positive test should never be accepted at any time. Such results always need confirmation. It is NOT necessary to confirm by a Western Blot test, even a repeat ELISA, done with another make of test kit gives reliable results and 3 ERS tests such as ELISA, spot test etc give as or even more dependable results than Western Blot.