What is the normal serum calcium range?

What is the normal serum calcium range?

• A. 8.0-9.0 mg/dL
• B. 8.6-10.2 mg/dL
• C. 9.5-11.5 mg/dL
• D. 10.0-12.0 mg/dL

Answer: (B)

Calcium in the blood is kept within a tight range because it supports muscle contraction, nerve signaling, cardiac function, and bone metabolism. For total serum calcium, the reference interval most labs use is about 8.6 to 10.2 mg/dL. This range reflects what’s typically seen in healthy individuals and allows for slight lab variation. Total calcium measures both the portion bound to albumin and the active ionized portion, so low albumin can make total calcium appear low even if ionized calcium is normal, which is important to consider in clinical assessment. Ionized calcium, the physiologically active form, is typically about 4.4 to 5.4 mg/dL. The other presented ranges fall outside the common normal limits, making 8.6-10.2 mg/dL the best choice.

Calcium in the blood is kept within a tight range because it supports muscle contraction, nerve signaling, cardiac function, and bone metabolism. For total serum calcium, the reference interval most labs use is about 8.6 to 10.2 mg/dL. This range reflects what’s typically seen in healthy individuals and allows for slight lab variation. Total calcium measures both the portion bound to albumin and the active ionized portion, so low albumin can make total calcium appear low even if ionized calcium is normal, which is important to consider in clinical assessment. Ionized calcium, the physiologically active form, is typically about 4.4 to 5.4 mg/dL. The other presented ranges fall outside the common normal limits, making 8.6-10.2 mg/dL the best choice.