What is the HIV RNA PCR test?
To understand what the HIV RNA PCR test is, we would have to go back to the life cycle of the HIV Virus.
HIV is a retrovirus. Retroviruses are a type of RNA virus that invades cells, in this case a kind of immune cells known as CD4 cells by injecting its genome directly into it. RNA is slightly different and less chemical complicated than DNA, hence the virus also has a special enzyme known as Reverse Transcriptase that will encode the HIV RNA into HIV DNA which is then merged with the host cell’s genome. Hence, if we can detect the presence of HIV RNA in the blood, we can be certain that there is HIV infection even without symptoms.
This is achieved through a technology known as polymerase chain reaction (PCR). In PCR, an automated device will process the patient’s sample with various chemicals. The polymerase enzyme and reaction will multiple any HIV RNA material into easily readable genetic information.
How is the test conducted?
A doctor or phlebotomist will draw a sample of blood for testing. It is no different from other kinds of blood testing and no fasting or special preparation is required.
How is this test different from other HIV tests?
As the HIV RNA PCR test is more sensitive, the window period is shorter and it can be used 12 days after exposure, as compared to 28 days for conventional Antibody/Antigen Testing.
However, only a few laboratories in Singapore are equipped to run this test. Hence HIV RNA PCR testing is more expensive than conventional HIV tests and can take up to 2 weeks for results to come back.
