What laboratory test should be monitored for a patient taking lithium?

Monitoring kidney function tests is essential for a patient taking lithium because lithium is primarily eliminated through the kidneys. The use of lithium can impact renal function, especially in patients who may have pre-existing kidney issues or who are dehydrated, as this can lead to increased serum lithium levels and potential toxicity.

Regular assessments of kidney function, often through measures such as serum creatinine and blood urea nitrogen (BUN), help ensure that the patient remains within the therapeutic range of lithium and identifies any changes that may indicate the onset of renal impairment. Monitoring these tests helps clinicians adjust the lithium dosage appropriately to minimize adverse effects and maintain patient safety.

While other tests, such as liver function tests, electrolyte levels, and complete blood counts, may also hold clinical significance for different reasons, they are not as directly relevant to lithium treatment as kidney function tests. Thus, the emphasis on monitoring kidney function is vital for safely managing patients on lithium therapy.