In hypoparathyroidism, phosphate levels in the blood are typically:

In hypoparathyroidism, phosphate levels in the blood are typically:

• A. Increased
• B. Normal
• C. Decreased
• D. Low-normal

Answer: (B)

Low parathyroid hormone reduces the kidney’s ability to excrete phosphate. PTH normally promotes phosphate wasting in the proximal tubule, so when PTH is deficient, phosphate reabsorption increases and serum phosphate rises. That’s why hypoparathyroidism typically shows hyperphosphatemia, alongside hypocalcemia. The phosphate level is not expected to be normal in this condition because the lack of PTH shifts the balance toward phosphate retention.

Low parathyroid hormone reduces the kidney’s ability to excrete phosphate. PTH normally promotes phosphate wasting in the proximal tubule, so when PTH is deficient, phosphate reabsorption increases and serum phosphate rises. That’s why hypoparathyroidism typically shows hyperphosphatemia, alongside hypocalcemia. The phosphate level is not expected to be normal in this condition because the lack of PTH shifts the balance toward phosphate retention.