Corrected Sodium for Hyperglycaemia Calculator
Hyperglycaemia dilutes serum sodium, so the measured value underestimates the true sodium. The correction adds a factor times the glucose excess over 100 mg/dL: the classic Katz factor is 1.6 and the Hillier factor is 2.4 mmol/L per 100 mg/dL of glucose above normal.
Quick answer
High blood glucose pulls water into the bloodstream and dilutes sodium, so the measured value reads low. The corrected sodium adds a factor times the glucose excess over 100 mg/dL: corrected Na = measured Na + factor × (glucose − 100) ÷ 100. The Katz factor is 1.6 and the Hillier factor is 2.4 mmol/L per 100 mg/dL.
Corrected sodium inputs
Correction is applied to glucose above 100 mg/dL only. No correction below 100 mg/dL.
How to use the Corrected Sodium calculator
- 1Enter the measured sodium and glucose. Enter the measured serum sodium (mmol/L) and the blood glucose (mg/dL).
- 2Read both corrected values. The tool applies both the classic Katz factor of 1.6 and the Hillier factor of 2.4 and shows the two corrected sodium estimates.
- 3Interpret with a clinician. The corrected sodium reflects the patient’s true sodium status once glucose is normalised; treatment of hyperglycaemia and any true sodium disturbance is decided by 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 does high glucose lower the measured sodium?⌄
Glucose is osmotically active, so marked hyperglycaemia draws water from cells into the blood, diluting the sodium concentration. This is "pseudohyponatraemia" of hyperglycaemia: the measured sodium is low even though total body sodium may be normal.
Should I use the 1.6 or 2.4 correction factor?⌄
Both are used. The classic Katz factor (1.6 mmol/L per 100 mg/dL of glucose above 100) is the traditional choice; Hillier’s later work suggested 2.4 is more accurate, especially at very high glucose levels. This tool shows both so a clinician can choose.
Does the correction change how hyponatraemia is treated?⌄
It can. Knowing the corrected sodium helps distinguish dilutional pseudohyponatraemia (which improves as glucose is treated) from a true sodium disturbance that needs separate management. The interpretation belongs to a clinician.
Is my data stored?⌄
No. The calculator runs entirely in your browser; nothing you enter is sent to a server.
Sources & validation
This calculator reproduces the published Corrected Sodium score, validated for estimating true serum sodium in the presence of hyperglycaemia.
- Katz MA. Hyperglycemia-induced hyponatremia — calculation of expected serum sodium depression (NEJM 1973;289:843-844) — the classic 1.6 mmol/L per 100 mg/dL factor — verified 2026-06-18
- Hillier TA, Abbott RD, Barrett EJ. Hyponatremia: evaluating the correction factor for hyperglycemia (Am J Med 1999;106:399-403) — proposes the higher 2.4 factor — verified 2026-06-18
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