text: <unk>  is a measure of the severity of a<unk>  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. Determination of<unk>  is part of the therapy monitoring during chronic<unk>  infections and in immunocompromised patients, e.g. after bone marrow or solid organ transplantation. Currently, routine testing is available for HIV-1, cytomegalovirus, hepatitis B virus, and hepatitis C virus.
option_0: Viral load
option_1: Nucleic acid test
option_2: Molecular microbiology
option_3: Hepatitis B surface antigen
option_4: HIV resistance testing
option_5: DNA sequencing
option_6: Microbiology
option_7: Enzyme assay