Calcium builds bones and teeth and is essential for muscles, nerves and heart rhythm. Blood calcium is tightly controlled by parathyroid hormone and vitamin D.
- Normal range (adults)
- 8.5–10.2 mg/dL (2.12–2.54 mmol/L)
- Sample
- Blood
- Fasting
- Not usually needed
- Also called
- Serum Calcium, Ca, Ca2+, S.Calcium, Total Calcium, Blood Calcium
Calcium normal range
| Group | mg/dLConventional units: US, South Asia | mmol/LSI units: UK, Europe, Australia, international |
|---|---|---|
| Adults | 8.5–10.2 | 2.12–2.54 |
Your report may use either unit system; labs in the Gulf often print both. Ranges also vary slightly between laboratories, so the range printed on your own report is the one to go by.
Why is the Calcium test done?
It is checked for bone health, kidney disease, parathyroid problems and when someone has muscle cramps or kidney stones.
What does a high Calcium level mean?
High calcium (hypercalcemia) can cause thirst, frequent urination, constipation, tiredness, confusion and kidney stones.
Common causes
- Overactive parathyroid gland (the most common cause)
- Excess vitamin D or calcium supplements
- Some cancers
- Dehydration
- Some medicines, such as thiazide diuretics
Diet and lifestyle tips
- Stop calcium and vitamin D supplements until your doctor reviews them
- Drink plenty of water
- Do not cut dietary calcium drastically without advice
What does a low Calcium level mean?
Low calcium (hypocalcemia) can cause tingling around the mouth and fingers, muscle cramps and spasms. A low albumin can make calcium look falsely low.
Common causes
- Vitamin D deficiency (very common in the Gulf and South Asia)
- Low albumin
- Low magnesium
- Kidney disease
- Underactive parathyroid, often after neck surgery
Diet and lifestyle tips
- Eat calcium-rich foods: milk, yogurt, laban, cheese, sesame (tahini), sardines with bones, leafy greens
- Get vitamin D from sunlight, oily fish, egg yolks and fortified foods
- Include magnesium sources: nuts, seeds, whole grains
When should you see a doctor?
Seek urgent care for spasms, severe tingling or confusion. Abnormal calcium should be rechecked with albumin, vitamin D and PTH.
Last updated
This page is for general education and is not a diagnosis. Normal ranges differ between laboratories, so always compare your result with the reference range printed on your own report, and discuss abnormal results with your doctor.