A tool to support the clinical decisions of doctors and health professionals, not for self-diagnosis or self-treatment.
This calculator is inside the patient's file in Clinicato: open it from "Medical tools" while you chart the visit, it fills in from the patient's details and vital signs where they are recorded, and adds its result to the visit's plan in one tap, with the "Medical tools" add-on. Try it in your clinic
Calculator
How it works and when to use it
Payne: corrected calcium (mg/dL) = total calcium + 0.8 × (4 − albumin in g/dL), since part of calcium is bound to albumin, so low albumin lowers total calcium without lowering free calcium.
The formula is approximate, and with very low albumin, critical illness or kidney failure ionised calcium is better measured directly.
Reference: Payne RB et al. BMJ 1973;4:643-6: corrected Ca (mg/dL) = Ca + 0.8 × (4 − albumin g/dL)
Frequently asked questions
When do I need ionised rather than corrected calcium?
In critical illness, acid-base disorders, kidney failure and very low albumin, where the correction is less accurate.
Is calcium corrected when albumin is normal?
No need, with an albumin of 4 g/dL corrected calcium equals total calcium.
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Try Clinicato for your clinic
These calculators are free here for everyone, and in Clinicato 49 medical tools work inside the patient's file with the "Medical tools" add-on: filled from the visit and the vital signs, with the result added to the visit's plan, next to appointments, prescriptions and invoices.