What it means
About half the calciumKAL-see-umA mineral that builds bones and teeth and that nerves, muscles, the heart and blood clotting need to work.Full entry in the blood is bound to proteins, mainly albumin; the free (ionized) half is the part that nerves, muscles and the heart actually use. The total calcium can mislead when the albumin is low or the blood's acid level is off, so the ionized calcium is checked in critically ill clients, during massive transfusion and after parathyroid or thyroid surgery.
For the nurse
The sample is handled carefully, often on ice and analyzed quickly, because exposure to air changes the result. Compare it with signs such as tingling, muscle cramps or twitching.
At a glance
| Normal range | About 4.6–5.3 mg/dL [1.15–1.33 mmol/L]; ranges vary by lab. |
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| Also written | free calcium, iCa |