Corrected Calcium Calculator (Albumin-Adjusted)
Corrected (albumin-adjusted) calcium estimates what the total serum calcium would be if albumin were normal, because low albumin lowers measured total calcium. The Payne formula adds 0.8 mg/dL for every 1 g/dL the albumin is below 4.0 g/dL.
Quick answer
Corrected (albumin-adjusted) calcium estimates total calcium as if albumin were normal, because low albumin lowers measured total calcium. The Payne formula (US units) is corrected calcium = measured calcium + 0.8 Γ (4.0 β albumin in g/dL). A typical reference is 8.5β10.5 mg/dL.
Corrected calcium inputs
How to use the Corrected Calcium calculator
- 1Enter total calcium and albumin. Enter the measured total serum calcium and the serum albumin. Choose US units (mg/dL, g/dL) or SI units (mmol/L, g/L).
- 2Read the corrected calcium. The tool applies the Payne formula and shows the albumin-corrected calcium.
- 3Compare to the reference range. The tool flags whether the corrected value is within, above or below the typical reference range, to interpret with a clinician.
Medical disclaimer: This is general health information, not medical advice. It does not diagnose or treat any condition, and the results are estimates based on public reference formulas. Always consult a qualified doctor about your individual health. If you think you may have a medical emergency, contact your local emergency services immediately.
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Book a consultationFrequently asked questions
Why correct calcium for albumin?β
About half of total calcium is bound to albumin, so a low albumin lowers the measured total calcium even when the physiologically active (ionised) calcium is normal. Correcting estimates what the total would be at a normal albumin.
Is corrected calcium accurate?β
The Payne correction is a rough estimate and can be unreliable, especially in critically ill patients and in chronic kidney disease. When precision matters, a direct ionised calcium measurement is preferred. A clinician decides.
What is the formula for corrected calcium?β
In US units: corrected calcium (mg/dL) = measured calcium + 0.8 Γ (4.0 β albumin in g/dL). In SI units: corrected calcium (mmol/L) = measured calcium + 0.02 Γ (40 β albumin in g/L).
Sources & validation
This calculator reproduces the published Corrected Calcium score, validated for albumin-adjustment of total serum calcium (Payne formula).
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