Sample Requirements:
Fasting sample preferred, SST tube
Purpose:
Evaluates hormonal and metabolic causes of weight gain or difficulty losing weight. Includes insulin, thyroid hormones, testosterone, vitamin D, and B12.
Reference Range:
Insulin (fasting): 2–25 µIU/mL; TSH: 0.45–4.5 µIU/mL; Vitamin D: 30–100 ng/mL; B12: 200–900 pg/mL