Calcium (Total)
Calcium is essential for bone strength, muscle contraction, nerve signalling, blood clotting, and many enzymatic processes. Most circulating calcium is bound to albumin; only the ionised (free) fraction is biologically active. Always interpret total calcium adjusted for albumin.
Normal Range
8.5–10.5 mg/dL (corrected for albumin)
Reference ranges may vary slightly between laboratories. Always interpret your result in context with your doctor.
Why is Calcium measured?
Calcium is part of the comprehensive metabolic panel. It is tested for bone disease, kidney disease, parathyroid disorders, certain cancers, and unexplained symptoms (cramps, neurological problems).
High Calcium means…
High calcium (hypercalcaemia) most commonly results from hyperparathyroidism or malignancy. Symptoms are remembered as 'stones, bones, abdominal moans, psychiatric groans' — kidney stones, bone pain, abdominal pain/constipation, and mood changes.
Low Calcium means…
Low calcium (hypocalcaemia) causes neuromuscular irritability — tingling around the mouth, muscle cramps, and tetany in severe cases. Causes include vitamin D deficiency, hypoparathyroidism, kidney disease, and pancreatitis.
Symptoms associated with abnormal Calcium
When Calcium is high:
- Excessive thirst, frequent urination
- Constipation, abdominal pain
- Kidney stones
- Confusion, depression
- Bone pain
- Fatigue
When Calcium is low:
- Tingling around mouth and fingers
- Muscle cramps and spasms
- Tetany (sustained muscle contraction)
- Seizures (severe)
- Brittle nails, dry skin
How to improve your Calcium
- Always correct calcium for albumin: corrected calcium = measured + 0.8 × (4.0 − albumin in g/dL).
- Persistent hypercalcaemia warrants parathyroid hormone (PTH) testing.
- Vitamin D deficiency is the easiest reversible cause of low calcium.
Frequently asked questions about Calcium
Why does albumin matter for calcium interpretation?
Most calcium is bound to albumin. If albumin is low, total calcium appears low even when ionised (active) calcium is normal. Corrected calcium adjusts for this.
Medical Sources
This page is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare provider about your individual results.