All calculators
Laboratory & Electrolytes
Corrected Calcium (for Albumin)
Correct serum calcium for hypoalbuminaemia to identify true hypercalcaemia or hypocalcaemia.
When to use: Use corrected calcium whenever serum albumin is below normal, as approximately 40–45% of serum calcium is protein-bound. Hypoalbuminaemic patients (liver disease, malnutrition, nephrotic syndrome) will have spuriously low total calcium even when ionised (free) calcium is normal. Corrected calcium unmasks true hypercalcaemia or reveals true normocalcaemia in patients with apparently low total calcium. For critical patients, measure ionised calcium directly on ABG where available.
Calculator
Normal ~4.0 g/dL
Fill in all fields to see the result
Formula
Corrected Ca (mg/dL) = Measured Ca + 0.8 × (4.0 − Albumin g/dL)
Normal: 8.5–10.5 mg/dL | Low <8.5: Hypocalcaemia | High >10.5: Hypercalcaemia
Key Points for NEET PG
- Calcium is 40–45% albumin-bound; fall in albumin = fall in total Ca even if ionised Ca is normal.
- Correction: add 0.8 mg/dL for every 1 g/dL drop in albumin below 4.0.
- Causes of hypercalcaemia (high Ca): "CHIMPANZEES" — Cancer (PTHrP), Hyperparathyroidism (primary), Immobility, Milk-alkali, Paget, Addison, Zollinger-Ellison (rare), Excess vitamin D, Sarcoidosis.
- Symptoms of hypercalcaemia: "Bones, Stones, Groans, Psychic Moans" — bone pain, kidney stones, constipation/nausea, depression/confusion.
- Hypocalcaemia causes: Chvostek sign (facial nerve tap) and Trousseau sign (carpal spasm with BP cuff) — classic NEET PG clinical signs.
References
Payne RB et al. Interpretation of serum calcium in patients with abnormal serum proteins · Br Med J (1973)
Lian IA, Asberg A. Should total calcium be adjusted for albumin? A retrospective observational study · BMJ Open (2018)
For educational purposes only. Not for clinical decision-making without professional oversight.