Family Nurse Practitioner Exam

What initial laboratory test should be performed for an 82-year-old patient who experienced a syncopal episode?

1. Urinalysis

2. Serum electrolytes

3. Blood glucose

4. Hemoglobin and hematocrit

The correct answer is: Blood glucose

For an 82-year-old patient who experienced a syncopal episode, the most appropriate initial laboratory test to perform is measuring the serum electrolytes. This decision is based on the fact that disturbances in electrolyte levels, such as sodium and potassium, can significantly contribute to dizziness, syncope, and even arrhythmias, especially in older adults who may have multiple comorbidities and may be on various medications that affect electrolyte balance. In the context of an elderly patient, dehydration, renal function decline, and cardiac issues are common factors that can lead to changes in electrolytes. By assessing serum electrolytes initially, healthcare providers can quickly identify any abnormalities that may need to be corrected or further investigated, thereby guiding appropriate management for the patient's symptoms. Other tests such as blood glucose, urinalysis, and hemoglobin and hematocrit are also useful in different scenarios. However, they are not the immediate priority in the context of unexplained syncope where electrolyte imbalances are a more pressing concern to rule out.