What lab value should be checked before administering mannitol?

Before administering mannitol, it is crucial to check serum electrolytes. Mannitol is an osmotic diuretic that works by drawing water into the renal tubules, increasing urine output and subsequently affecting fluid and electrolyte balance. Monitoring serum electrolytes, particularly sodium and potassium levels, is important because mannitol can lead to alterations that may cause hypernatremia or other electrolyte imbalances due to shifts in fluid and solute distribution in the body.

While the other lab values mentioned could be important in various clinical situations, they are not specifically relevant to the direct effects of mannitol. Serum glucose is primarily monitored in conditions like diabetes, while complete blood count is more related to infection or blood disorders, and liver function tests are essential in assessing liver health, but none directly address the immediate physiological changes induced by mannitol. Thus, checking serum electrolytes prior to administration helps ensure patient safety and effective management of any potential complications arising from osmotic therapy.