Questions: Scenario: A 37-year-old male with bipolar disorder is on valproate and presents with fatigue, weight gain, and hair loss. What laboratory test should be ordered? Complete blood count (CBC) Liver function tests (LFTs) Thyroid function tests (TFTs) Serum ammonia level

The answer is the third one (or C): Thyroid function tests (TFTs).

Explanation for each option:

1. Complete blood count (CBC): While a CBC can provide valuable information about overall health and detect a variety of disorders such as anemia, infection, and many other diseases, it is not specifically indicated for the symptoms of fatigue, weight gain, and hair loss in the context of a patient on valproate.

2. Liver function tests (LFTs): Valproate can affect liver function, and LFTs are important for monitoring liver health in patients taking this medication. However, the symptoms of fatigue, weight gain, and hair loss are more suggestive of thyroid dysfunction rather than liver issues.

3. Thyroid function tests (TFTs): These tests are the most appropriate in this scenario. Fatigue, weight gain, and hair loss are classic symptoms of hypothyroidism, which can be a side effect of valproate. Therefore, checking thyroid function is crucial to determine if the patient has developed hypothyroidism.

4. Serum ammonia level: Elevated serum ammonia levels can occur in patients on valproate and can lead to symptoms such as confusion, lethargy, and altered mental status. However, the symptoms described (fatigue, weight gain, and hair loss) are not typically associated with elevated ammonia levels.

Summary: Given the symptoms of fatigue, weight gain, and hair loss in a patient on valproate, the most appropriate laboratory test to order is Thyroid function tests (TFTs) to check for hypothyroidism.