How to interpret mycophenolic acid levels

• Serum trough levels of mycophenolic acid (MPA) at steady-state (>2weeks at the same dose) in the range of 1.0-3.5 mcg/mL indicate adequate therapy. MPA is the active metabolite.
• Mycophenolic acid glucuronide (MPA-G) levels in the range of 35 to 100 mcg/mL indicate that the patient has normal uridine diphosphate glucuronosyltransferase (UGT) metabolic capacity. MPA-G is inactive and describe the patient’s metabolic status.
• Trough steady-state serum MPA levels >4.0 mcg/mL indicate that the patient is overimmunosuppressed and susceptible to systemic infections.
• Decreased dosages may be indicated in these cases.
• Low MPA levels and high MPA-G levels suggest that the patient has an active UGT metabolic capability; higher doses may be required to maintain therapeutic levels of MPA.
• Patients who have low UGT conjugating capability may become overimmunosuppressed, indicated by a trough steady-state serum MPA level >4.0 mcg/mL and a MPA-G level <40 mcg