Surrogate markers

A surrogate marker is an indirect measure. In HIV disease, morbidity and mortality are direct markers of disease progression; laboratory tests are surrogate markers of disease progression. Changes in these markers have been shown to affect the long-term risk of death and illness. Surrogate markers in HIV disease include CD4 counts, CD4/CD8 cell ratios, and viral load. Surrogate markers are important in anti-HIV drug trials because the true effects of drugs in slowing HIV disease may not be obvious for many years. Changes in surrogate markers can quickly reveal whether treatment will have any long-term benefits.

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