Which test is not considered routine monitoring for patients taking lithium?

In the context of monitoring patients who are prescribed lithium, the appropriate routine tests are critical for ensuring both efficacy and safety. While all the tests listed serve important roles in overall patient management, routine monitoring specifically focuses on lithium levels and potential side effects from its use.

Serum electrolytes, including sodium levels, are essential because lithium can influence renal function and electrolyte balance. The complete blood count may also be performed in certain cases to monitor for any hematological effects, although it is not as directly related to lithium use.

Blood urea nitrogen and creatinine are vital for assessing renal function since lithium excretion occurs through the kidneys, and its levels can affect kidney health. Regularly monitoring these values helps prevent potential nephrotoxicity.

On the other hand, a 24-hour urine collection for creatinine and protein is not standardized in the routine monitoring of lithium treatment. While it can provide information on renal function and the presence of proteinuria, it is not performed routinely like the other blood tests. This procedure is typically reserved for specific clinical situations rather than as a routine evaluation for all patients on lithium therapy. Thus, it is the least relevant in the context of regular monitoring needs for patients on lithium.