In Tanzania, CD4+ T-lymphocyte count is the gold standard method used to determine the time for initiation and change of therapy. Each patient should have a baseline CD4+ T-lymphocyte count (and viral load where possible) done before initiating treatment. CD4+ T-lymphocyte count should then be repeated at least every 6 months. Treatment will in most cases be associated with weight gain and reduced morbidity from opportunistic infections and improvement in the quality of life. Appearance or persisting opportunistic infections, or lack of weight gain, may indicate treatment failure and so the need to consider changing regimens.
Treatment is to be considered successful if the viral load decreases by 1 to 2 logs (10 to 100 folds) from the baseline level. However in most cases, CD4+ will be used instead of viral load thus a rise in CD4+ T-lymphocyte count will indicate success.
Treatment failure on the other hand is indicated by a viral load increase of 0.3 to 0.5 logs or a 30% fall in CD4+ T-lymphocyte count.