In a case of an elderly woman who may have fainted, what is the initial lab test important to perform?

In the context of an elderly woman who may have fainted, obtaining a blood glucose level is critical as an initial lab test. Hypoglycemia, or low blood sugar, is a common and potentially reversible cause of fainting, especially in elderly patients who may have diabetes or are on medications affecting glucose metabolism. Rapid assessment of blood glucose can help rule out this acute and treatable condition.

If the blood glucose level is found to be low, immediate intervention can be initiated to correct it and potentially alleviate the fainting episode. The importance of checking blood glucose lies in the fact that it may require urgent treatment, especially if the patient is symptomatic. Ensuring the patient's safety through monitoring and intervention can significantly impact their outcome.

While serum electrolytes, urinalysis, and hemoglobin and hematocrit are valuable tests, they are typically considered in a broader evaluation after ruling out more immediate life-threatening causes, such as hypoglycemia.