When should I use this?

Whenever a patient has hypoalbuminemia (low protein), which is common in malnutrition, liver disease, and critical illness.

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Medical

Corrected Calcium – Electrolyte Accuracy Service | CalcTools

Correct total calcium levels for albumin. Essential electrolyte service for acute care.

Standard lab reports for 'Total Calcium' can be highly misleading in sick patients. Because half of the calcium in the blood is bound to the protein albumin, low protein levels will make it look like a patient has a calcium deficiency when their 'active' calcium is actually normal. Our Corrected Calcium service solves this problem by normalizing the result against the patient's albumin level, providing the true physiological picture of their electrolyte status.

Educational use only. This tool does not replace clinical judgment or local protocols.

Measured Calcium

Albumin level

Units

Note: Albumin affects total Ca.

Final Ca

2.2mmol/L

Corrected Calcium is 2.2 mmol/L

Ca + 0.02 * (40 - Alb) = 2.1 + 0.02 * (40 - 35)

Measured Calcium2.1 mmol/L

Albumin level35 g/L

Unitsmmol/L

How it Works

The tool applies the Payne formula, which adds 0.8 mg/dL to the calcium result for every 1 g/dL that the albumin is below the standard reference of 4.0.

Calculation Formula

Ca_corr = Ca_meas + 0.8 × (4.0 - Albumin)

Calculation Examples

1. **Low Protein**: Ca 8.0, Albumin 2.0 = **9.6 (Normal)**.

Why use this tool in your daily life?

Avoid unnecessary treatments. This service prevents the dangerous and costly administration of IV calcium to patients who don't actually need it, keeping electrolyte management safe and evidence-based.