The polymerase chain reaction (PCR) test used to detect human immunodeficiency virus (HIV) is typically considered to be very accurate, although there are several factors that come into play. The test is highly sophisticated and must be read by healthcare professionals who are well trained in deciphering the results. In most cases, the PCR test is not used for routine HIV testing except for in infants who are born to an HIV-positive mother.
There are several types of HIV test and each one has its own level of accuracy. Rapid response tests are typically considered the least accurate, while antibody tests and PCR tests are the most accurate. Antibody tests are the most commonly used because they are extremely reliable when used at least three months after potential exposure. The accuracy of a PCR HIV test is not fully understood, but they are considered fairly accurate for use under certain circumstances.
When considering how accurate a PCR HIV test might be, several factors play a role. The first involves the skills of the laboratory staff reading the test. PCR tests use advanced screening methods to pick up on the genetic material of HIV rather than antibodies. It is not an easy test to read and decipher, so many false results may be caused by human error. Only those who are fully trained and experienced in reading and performing the test should do so when testing for HIV.
Another variable is the length of time between when a person is exposed to the virus and testing. While both the PCR and antibody tests can usually detect traceable levels of the virus within a few weeks after exposure, both tests are most accurate at three months past exposure. No matter which type is used, a follow-up test is always performed to ensure that results are as accurate as possible.
Use of the PCR test for HIV is not done on a routine basis in most situations because it is difficult and expensive to administer. Many labs do not have the right equipment to perform these tests. The PCR test may be used in newborns born to an HIV-positive mother since antibodies from the mother’s bloodstream can continue to show up in the infant’s blood tests for several months after birth even if he or she is HIV-negative. This makes the accuracy of the test more reliable in these cases.