Correction of lithium levels for dose and blood sampling times.

Inconsistencies inherent in the clinical application of morning serum lithium levels can be eliminated by correcting the levels for variations in dosage schedule, rate of lithium elimination, and blood sampling time. In this report, graphs constructed from an accurate pharmacokinetic model of lithium elimination are used to convert the serum lithium level into the daily exposure of the body to lithium. This method facilitates safety and effectiveness in lithium treatment and enables outpatient blood samples for lithium levels to be conveniently drawn in the afternoon.