Calcium, Ionized
Ionized calcium measures only the free, active calcium in your blood, the portion not bound to proteins. This is the form your body actually uses.
Because it isn't affected by your albumin level, ionized calcium can be a more precise measure of calcium status than total calcium, especially when protein levels are abnormal or in critical care settings.
A higher ionized calcium may point to overactive parathyroid glands or other calcium-raising conditions. As with total calcium, it's interpreted alongside your symptoms and related hormone tests.
A lower ionized calcium can relate to hormonal or vitamin D factors and may cause symptoms like tingling if significant; mild changes are evaluated in context.
A typical range is roughly 4.6 to 5.3 mg/dL (about 1.15 to 1.33 mmol/L), and it's sensitive to sample handling. Your clinician can interpret your value.
Sources
Educational context only, not medical advice or a diagnosis. Reference ranges vary by lab, age and sex; always discuss your results with a clinician.