Branched DNA testing or bDNA testing is a test created by the Chiron company to measure the viral load of HIV in a sample of blood. A phosphorescent chemical that is known to bind to HIV RNA 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 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.