Calcium, Ionised (Ca²⁺) Test

The Calcium, Ionised (Ca²⁺) Test measures the biologically active fraction of calcium circulating in your blood. Unlike total calcium, which is influenced by albumin and other binding proteins, ionised calcium reflects the calcium that is immediately available to your cells. This makes it a vital test when accurate assessment of calcium status is essential, particularly in situations where total calcium may be misleading.

This test is typically requested for patients in critical care, those undergoing major surgery, or individuals with conditions that affect calcium regulation such as kidney disease, pancreatitis, or parathyroid disorders. It is also valuable when symptoms of abnormal calcium levels are present, including muscle cramps, tingling, confusion, or cardiac arrhythmias. Because ionised calcium is not bound to proteins, it provides a direct window into the physiologically active mineral balance that supports nerve conduction, muscle contraction, blood clotting, and hormone secretion.

Biomarkers
- Calcium, ionised (Ca²⁺)

Why it matters
Ionised calcium is the form your body actually uses. Measuring it directly helps your doctor detect and monitor real-time calcium imbalances that can affect heart rhythm, nerve function, and muscle performance, especially when total calcium results might be unreliable due to low or abnormal protein levels. This test supports precise clinical decisions in urgent and complex care settings.

• Calcium, ionised (Ca²⁺)

No special preparation required.

For blood tests, we recommend drinking plenty of water beforehand to ensure smooth sample collection. If you are taking any regular medication, continue to do so unless advised otherwise by your doctor.