Bedford Research Foundation research programs use the most precise form of HIV testing available for semen.
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 (back cover).
The PCR HIV DNA assay took several years to develop. It is a molecular biology test similar to the one used for quantitation of blood virus, but more sensitive because of the small size of the semen specimen. It is designed to detect both free virus and virus infected cells. (The assays have not been FDA approved.)
The first step is to convert all the HIV-RNA to HIV-DNA using RT1. Second, the 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 electrophoresis through agarose gels or an Agilent Bioanalyzer. 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 assay tube that contains HIV-specific reagents.
Although commonly considered one of the most accurate and specific HIV tests available – PCR testing is not typically used for standard HIV blood tests because the time consuming process is expensive.