Corrected Sodium in Hyperglycaemia: An Estimate, Not a Correction Target

Quick Medical Calculator · Reading label 24 September 2026 · 3 min read

Retrospective study sequence, not publication date

Retrospective educational series: 17 September to 16 October 2026. This coverage window is not the publication date.

An estimated sodium adjusted for hyperglycaemia is not a second laboratory measurement. It is a model-based way to consider the effect of glucose-associated water shifts. Calling it "corrected" should not make it a target concentration or a prescription for correcting the measured sodium.

Keep the Measured Value Visible

For a fictional adult, measured sodium is 128 mmol/L and glucose 500 mg/dL. Using a coefficient of 1.6 mmol/L per 100 mg/dL of glucose above 100:

128 + 1.6 x ((500 - 100) / 100) = 134.4 mmol/L.

Using 2.4 instead gives 137.6 mmol/L. The laboratory sodium remains 128. The two estimates differ because the coefficient changed, not because a new specimen was tested.

The site's Sodium Correction calculator uses the 1.6 convention. It does not offer a switch that validates 2.4 for an individual. The second value above is a separate educational comparison. If entering glucose in mmol/L, use the unit control and do not place 500 into an SI field. With the site's glucose factor, 500 mg/dL is approximately 27.75 mmol/L.

Read the Evidence Behind the Alternative Coefficient

Hillier and colleagues studied experimental hyperglycaemia in six healthy volunteers. The abstract reports an overall sodium-glucose association of 2.4 per 100 mg/dL and a nonlinear relationship. That small physiological experiment is useful for questioning a fixed universal correction, but it is not a trial of fluid choice in acutely ill people. It does not establish a best coefficient for every patient. Original study.

Only the abstract of that study was accessed for this draft. Its coefficient should not be presented as a precisely validated personal prediction or as evidence for a particular sodium-correction rate.

A Changing Sodium Needs a Dynamic Assessment

During treatment of a hyperglycaemic crisis, measured sodium can rise as glucose falls. The 2024 adult consensus explicitly cautions that the initial sodium rise alone does not justify switching to hypotonic fluid. Decisions require assessment of osmolality, fluid balance and the wider clinical situation. Adult consensus report.

This article intentionally provides no fluid volume, insulin regimen, replacement deficit or safe-rate instruction. Those require the applicable clinical pathway and repeated observations. A calculator result or its category cannot replace that process, and adult assumptions should not be transferred to pregnancy or paediatric care.

Check the handover: Record measured sodium and glucose, specimen time, the coefficient used and the resulting estimate. Keep subsequent measured results separate. Writing only "sodium 138 after correction" hides both the original measurement and the model uncertainty.

The useful conclusion is not that one coefficient produces the correct answer. It is that a single estimated value must not be allowed to conceal changing physiology or dictate treatment.

Reading label: 24 September 2026. Day 8 of the retrospective educational series. This is a reading-sequence date, not a publication or clinical-review date.