Serum (Brown) Lithium heparin (orange) samples must not be used.
8hrs
Lithium is a widely used drug for the treatment of psychosis. Estimation of serum lithium levels may be useful when establishing a dosage for new patients, monitoring compliance or assessing for suspected toxicity due to the narrow therapeutic range.
Blood samples for serum lithium determinations should be drawn immediately prior to the next dose when lithium concentrations are relatively stable (i.e., 8-12 hours after the previous dose). Total reliance must not be placed on serum levels alone. Accurate patient evaluation requires both clinical and laboratory analysis. Elderly patients often respond to reduced dosage, and may exhibit signs of toxicity at serum levels ordinarily tolerated by younger patients.
Target therapeutic range 0.4-1.0 mmol/L (long term treatment. Acute psychosis may require a higher concentration). Concentrations >1.5mmol/L are at risk of toxicity
Printer-friendly version
