⚖️ Electrolytes & Minerals

Calcium: What It Means for Your Health

Calcium is the most abundant mineral in the human body, with 99% stored in bones and teeth. The remaining 1% circulates in blood and is essential for muscle contraction, nerve transmission, blood clotting, and enzyme function. Blood calcium is tightly regulated by parathyroid hormone (PTH), vitamin D, and calcitonin. Total calcium includes both bound (to albumin) and free (ionized) forms; low albumin can falsely lower total calcium.

Full Name
Serum Calcium (Ca2+)
Normal Range
8.5–10.5 mg/dL
Also Known As
Ca, Ca2+

Reference Range

LowNormal: 8.5–10.5 mg/dLHigh

Reference ranges may vary between laboratories, age groups, and sexes. The values shown are general adult reference ranges. Always compare your results to the specific range provided by your testing laboratory.

What Is Calcium?

Calcium is the most abundant mineral in the human body, with 99% stored in bones and teeth. The remaining 1% circulates in blood and is essential for muscle contraction, nerve transmission, blood clotting, and enzyme function. Blood calcium is tightly regulated by parathyroid hormone (PTH), vitamin D, and calcitonin. Total calcium includes both bound (to albumin) and free (ionized) forms; low albumin can falsely lower total calcium.

Commonly included in:

Basic Metabolic Panel (BMP)Bone PanelComprehensive Metabolic Panel

What Does High Calcium Mean?

Above 10.5 mg/dL

Elevated calcium (hypercalcemia) is most commonly caused by primary hyperparathyroidism and cancer (bone metastases, parathyroid hormone-related peptide). Other causes include excessive vitamin D or calcium supplementation, thyroid disorders, sarcoidosis, and prolonged immobilization. Symptoms include fatigue, nausea, constipation, kidney stones, bone pain, and confusion.

What Does Low Calcium Mean?

Below 8.5 mg/dL

Low calcium (hypocalcemia) can cause muscle cramps, spasms (tetany), numbness/tingling (paresthesias), cardiac arrhythmias, and seizures. Common causes include vitamin D deficiency, hypoparathyroidism, kidney disease, magnesium deficiency, pancreatitis, and certain medications. Low albumin can cause falsely low total calcium readings.

Related Biomarkers in Electrolytes & Minerals

Sodium
Key electrolyte that regulates fluid balance, blood pressure, and nerve function.
Range: 136–145 mEq/L
Potassium
Essential electrolyte for heart rhythm, muscle function, and nerve signaling.
Range: 3.5–5 mEq/L
Magnesium
Essential mineral involved in over 300 enzymatic reactions in the body.
Range: 1.7–2.2 mg/dL
Phosphorus
Mineral important for bones, teeth, energy production, and DNA.
Range: 2.5–4.5 mg/dL
Zinc
Essential trace mineral for immune function, wound healing, and taste/smell.
Range: 60–120 ug/dL

Track Your Calcium Over Time

Upload your blood test results to Hemoly and see how your Calcium levels change over time. Get trend analysis, educational insights, and a personal health timeline.

Download Hemoly for iOS

Medical Disclaimer

This information is for educational purposes only and is not intended as medical advice, diagnosis, or treatment. Reference ranges may vary between laboratories. Always consult a qualified healthcare professional for interpretation of your blood test results and before making any health decisions.