For patients with xanthelasma, aside from a lipid panel, do you perform any additional lab workup or send referrals?   

It is reasonable to get a lipid panel and screening thyroid dysfunction labs (tsh, t4, and t3). Since xanthelasma are benign but often recur, I think an important aspect here is managing expectations. Let the patient know that recurrence is common and not associated with poor surgical techniques.

Agree that recurrence is common, but there are no data that a high cholesterol or increased serum lipid is associated with them.