Metabolic
Calcium
LOINC 17861-6 · mg/dL
Ranges
Reference range: 8.5–10.5 mg/dL
What it is
Calcium in the blood is a mineral essential for bones, nerves, muscles and clotting. The body keeps it in a tight range.
Why it matters
Because levels are tightly controlled by hormones and the kidneys, an abnormal calcium can flag a parathyroid, kidney, bone or vitamin-D issue.
What high values can mean
A higher value can relate to overactive parathyroid glands, some medications or, less often, other conditions.
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 targets the cause; adequate vitamin D and a balanced intake of calcium support normal levels.
Food & lifestyle
Dairy, leafy greens, tofu and fortified foods provide calcium; vitamin D helps you absorb it.
Preparing for the test
Often part of a metabolic panel; fasting is not specifically required for calcium — follow your lab.
When to talk to a doctor
Discuss a persistently high or low calcium with a doctor, who may check 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.
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