Which laboratory pattern is typical of hypocalcemia?

Which laboratory pattern is typical of hypocalcemia?

• A. Low ionized calcium and low total calcium
• B. High calcium and high phosphate
• C. High magnesium and high calcium
• D. Low potassium and normal calcium

Answer: (A)

Calcium homeostasis is best assessed by the physiologically active portion, ionized calcium. While total calcium can be misleading because it depends on albumin binding, true hypocalcemia is reflected by a low ionized calcium. When both ionized calcium and total calcium are reduced, it indicates genuine hypocalcemia rather than a situation where total calcium is low only because albumin is low. Other patterns don’t fit hypocalcemia as well. A high calcium (with or without high phosphate) would point away from hypocalcemia. A pattern with high magnesium and high calcium isn’t typical for low calcium states. Low potassium with normal calcium doesn’t describe low calcium.

Calcium homeostasis is best assessed by the physiologically active portion, ionized calcium. While total calcium can be misleading because it depends on albumin binding, true hypocalcemia is reflected by a low ionized calcium. When both ionized calcium and total calcium are reduced, it indicates genuine hypocalcemia rather than a situation where total calcium is low only because albumin is low.

Other patterns don’t fit hypocalcemia as well. A high calcium (with or without high phosphate) would point away from hypocalcemia. A pattern with high magnesium and high calcium isn’t typical for low calcium states. Low potassium with normal calcium doesn’t describe low calcium.