The PCR Test for HIV in Semen
SPAR uses the most precise form of HIV testing available.
The specimen is divided into three portions – one portion is RT-PCR tested for HIV, a second portion is immunostained for cells of the immune system. Sperm are recovered from the third portion, washed, and cryopreserved in liquid nitrogen.
The RT-PCR HIV assay took several years to develop. It is a molecular biology test similar to the one used for blood, but more sensitive because of the small size of the semen specimen. It is designed to detect both free virus and HIV-infected cells. The assays have been FDA inspected, and have been approved by federal and state clinical laboratory inspection programs.
The first step is to convert all the HIV-RNA to HIV-DNA using RT1. Second, the HIV-DNA in the sample must be amplified by PCR1.
The process of amplification allows a small number of copies of HIV-DNA to be detected by flourescent probe. A normal cellular gene is amplified in the same test to serve as an internal control.
1 RT-PCR stands for Reverse Transcription – Polymerase Chain Reaction. Reverse Transcription (RT) uses a specific enzyme to convert RNA to DNA.
The Polymerase Chain Reaction (PCR) amplifies highly specific DNAs by employing repeat cycles of heating and cooling to the tube that contains HIV-specific reagents.
Although considered one of the most accurate HIV tests – it is not typically used for HIV blood tests because the time consuming process is expensive.