Metabolic
Ionized Calcium
LOINC 1994-3 · mmol/L
Ranges
Reference range: 1.12–1.32 mmol/L
What it is
Ionized calcium is the active, free portion of calcium in your blood — the part the body actually uses, not bound to proteins.
Why it matters
It gives a precise read of calcium status, useful when total calcium or protein levels make interpretation tricky.
What high values can mean
A higher value can relate to overactive parathyroid glands or other conditions affecting calcium.
What low values can mean
A lower value can relate to vitamin-D deficiency, kidney issues or low parathyroid activity.
How to improve it
Management addresses the underlying cause; adequate vitamin D and balanced calcium intake support normal levels.
Food & lifestyle
Dairy, leafy greens and fortified foods provide calcium; vitamin D aids absorption.
Preparing for the test
A blood test sometimes requiring specific handling; fasting is not generally required — follow your lab.
When to talk to a doctor
Discuss an abnormal ionized calcium with a doctor, often alongside vitamin D and parathyroid hormone.
Related markers
Sources
- MedlinePlus (NIH)
- Testing.com (AACC)
Content reviewed on June 26, 2026
Medical disclaimer
This content is for educational purposes only. It is not medical advice and does not diagnose, treat, or prevent any condition. Reference ranges vary between laboratories — always use the range printed on your report and discuss your results with a healthcare professional.
See your own values in context
Bllod turns your lab report PDFs into clear, tracked results — every marker organized, explained, and charted over time.