Definitions for "Surrogate markers"
Levels of cells or proteins that indirectly indicate HIV activity and are used to mark disease progression.
evidence of a condition. The most common HIV tests look for HIV antibodies instead of the actual virus. Those antibodies (or footprints) indicate the virus is present. Surrogate markers are used when they are easier to find than the actual organism.
Variables (measures) that are followed in clinical trials when the variable of the primary interest cannot conveniently be observed in a direct manner. Two commonly used surrogate markers in HIV studies are CD4+ T cell counts and quantitative plasma HIV RNA (viral load).