Branched DNA testing or bDNA testing is a test created by the Chiron company to measure the viral load

Viral load

Viral load is a measure of the severity of a viral infection, and can be calculated by estimating the amount of virus in an involved body fluid. For example, it can be given in RNA copies per milliliter of blood plasma...

 of HIV

HIV

Human immunodeficiency virus is a lentivirus that causes acquired immunodeficiency syndrome , a condition in humans in which progressive failure of the immune system allows life-threatening opportunistic infections and cancers to thrive...

 in a sample of blood. A phosphorescent chemical that is known to bind to HIV RNA

RNA

Ribonucleic acid , or RNA, is one of the three major macromolecules that are essential for all known forms of life....

 is added to the suspect DNA. The more brightly the test sample glows, the greater amount of HIV present in the sample, and this test is used to directly measure the amount of virus in a given sample. It is accurate enough to identify as few as twenty-five virus particles in a given sample, although in the early stages of HIV infection this test may give a false negative due to the initial low amount of virus in the blood. Since it costs significantly more than the standard ELISA

ELISA

Enzyme-linked immunosorbent assay , is a popular format of a "wet-lab" type analytic biochemistry assay that uses one sub-type of heterogeneous, solid-phase enzyme immunoassay to detect the presence of a substance in a liquid sample."Wet lab" analytic biochemistry assays involves detection of an...

antibody test and does not usually detect the virus in the early stages of infection, the bDNA test is usually recommended for those already diagnosed with HIV/AIDS in order to aid in treatment possibilities.