Corrected Calcium for Albumin
Estimate albumin-corrected serum calcium with Payne's formula: corrected Ca = measured Ca + 0.8 x (4.0 - albumin g/dL).
Open the calculator → Runs in your browser. Data leaves only if you deliberately send a problem report from the interactive tool.
Example
- Measured calcium
- 8.0 mg/dL
- Albumin
- 2.0 g/dL
Result: Corrected Ca 9.6 mg/dL
The tool opens with these values already filled in. Replace them with your own.
What you enter
- Measured calcium
- Albumin
What this is
Sophie Well returns the corrected value and flags hypo- or hypercalcemia against the conventional reference range. Source: Payne RB et al, BMJ 1973.
When to use it
Use this when albumin is abnormal (hypoalbuminemia under-reports total calcium even when the ionized fraction is normal) and an ionized calcium is not immediately available. Albumin correction is a screening estimate, not a substitute for ionized calcium in critical illness, acid-base derangement, or paraproteinemia - in those settings, draw the ionized value.
How this is calculated
Payne RB, et al. Interpretation of serum calcium in patients with abnormal serum proteins. BMJ. 1973;4(5893):643-646. Read the source ↗
A reference and educational tool. Not medical, legal, or financial advice, and not a substitute for clinician judgment.
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