Hypocalcemia Laboratory Evaluation Serum levels of PTH, phosphorus, 25-hydroxyvitamin D, and 1,25-dihydroxyvitamin D can help differentiate between disorders causing hypocalcemia: - Hypoparathyroidism - Calcium-sensing receptor activating mutation - Parathyroid hormone resistance (pseudohypoparathyroidism) - Vitamin D deficiency - Chronic kidney disease #Hypocalcemia #Laboratory #Levels #Hyperparathyroidism #Diagnosis #Endocrinology #Differential