Medicine A 35 year old male known case of MEN 1 presents to OPD with urinary stones and increased serum calcium. Next investigation to be done is? A Urinary Metanephrine B Secretin study C Serum calcitonin levels D 72 hour prolonged fasting 💡 Explanation A 35 year old male known case of MEN 1 presents to OPD with urinary stones and increased serum calcium. Next investigation to be done is? ✓ Correct Answer: B. Secretin study