What this marker measures
Serum calcium is partially bound to albumin. If albumin is low, the measured calcium will appear falsely low — a "corrected calcium" value is often calculated to account for this.
High or low: what it can mean
High Calcium
Elevated blood calcium (hypercalcemia) is most commonly caused by overactive parathyroid glands or, less commonly, malignancy, excess vitamin D, or certain medications. Mild elevations may be asymptomatic.
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Low Calcium
Low blood calcium (hypocalcemia) can cause muscle cramps, tingling, or more severe symptoms at very low levels. Causes include low vitamin D, low magnesium, kidney disease, or underactive parathyroid glands.
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Lifestyle considerations
- •Adequate vitamin D is essential for calcium absorption from the intestine
- •Weight-bearing exercise helps maintain bone calcium over time
Frequently asked questions
What is Calcium?
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Calcium is essential for bone and teeth structure, muscle contraction, heart function, nerve signalling, and blood clotting. About 99% of the body's calcium is stored in bones.
What does Calcium measure?
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Serum calcium is partially bound to albumin. If albumin is low, the measured calcium will appear falsely low — a "corrected calcium" value is often calculated to account for this.
What does high Calcium mean?
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Elevated blood calcium (hypercalcemia) is most commonly caused by overactive parathyroid glands or, less commonly, malignancy, excess vitamin D, or certain medications. Mild elevations may be asymptomatic.
What does low Calcium mean?
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Low blood calcium (hypocalcemia) can cause muscle cramps, tingling, or more severe symptoms at very low levels. Causes include low vitamin D, low magnesium, kidney disease, or underactive parathyroid glands.
What supports healthy Calcium levels?
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Adequate vitamin D is essential for calcium absorption from the intestine. Weight-bearing exercise helps maintain bone calcium over time
Related biomarkers
Editorial note
LabTestly explains lab markers using plain-English educational content. Reference ranges may vary by laboratory and should be interpreted with a clinician.
Educational content · Editorially reviewed for clarity · Last updated
Common sources used for lab-test education
Not medical advice
This page is for general understanding only and does not replace medical advice from your clinician. Reference ranges can vary by laboratory, age, sex, pregnancy status, medications, and clinical context.