What is the Corrected sodium for hyperglycaemia?
EvidenceMD's corrected sodium calculator adds 1.6 mmol/L to the measured sodium for every 100 mg/dL (5.6 mmol/L) of glucose above 100 mg/dL — Katz's factor — and shows Hillier's factor of 2.4 alongside [1][2]. Hillier found the 1.6 factor worked well up to a glucose of 400 mg/dL, with a larger correction better above that [2]. Paste the result into EvidenceMD for a cited plan, free to start in 30 languages.
Key takeaways
- Katz: corrected Na = Na + 1.6 × (glucose − 100) ÷ 100, with glucose in mg/dL [1].
- Hillier: 2.4 per 100 mg/dL overall; 1.6 worked well up to 400 mg/dL, and 4.0 was better above it [2].
- A normal corrected sodium means the low measured value is explained by glucose; a low corrected value means true hyponatraemia [1][2].
- A high corrected sodium in hyperglycaemia points to a free water deficit despite the low measured value.
- EvidenceMD turns the result into a plan — fluids, insulin and sodium monitoring — with citations, free to start.
How is the Corrected sodium for hyperglycaemia calculated?
Enter the measured sodium and glucose from the same sample.
| Input | Definition | Role |
|---|---|---|
| Measured sodium | Units: mmol/L or mEq/L. | Formula input |
| Glucose | Units: mg/dL or mmol/L. | Formula input |
→ Scroll the table sideways to see the remaining columns
How do you interpret the Corrected sodium for hyperglycaemia result?
The category reads the Katz value against the usual range of 135–145 mmol/L; the Hillier value is shown under the result.
| Result | Category | What it means |
|---|---|---|
| < 135 | Low after correction | The sodium is still below 135 mmol/L after allowing for glucose, so true hyponatraemia is present. Check serum osmolality. |
| 135–145 | Within the usual range | The low measured sodium is explained by the glucose (translocational hyponatraemia). |
| > 145 | High after correction | The corrected sodium is above 145 mmol/L: the patient has a free water deficit despite the low measured value. |
→ Scroll the table sideways to see the remaining columns
Hillier and colleagues raised glucose above 600 mg/dL in six healthy volunteers: sodium fell by an average of 2.4 mmol/L per 100 mg/dL, and the relationship was not linear, with 1.6 adequate up to 400 mg/dL and 4.0 better above it [2].
When should you use the Corrected sodium for hyperglycaemia?
Use it in hyperglycaemia, such as diabetic ketoacidosis or the hyperosmolar hyperglycaemic state, to tell translocational from true hyponatraemia and to follow sodium as glucose falls [1][2].
When not to use it
It corrects only for glucose: measure serum osmolality, and consider other osmoles such as mannitol, which also lower sodium. Both factors are estimates from small studies [2].
What is the evidence behind the Corrected sodium for hyperglycaemia?
Katz calculated in 1973 that sodium falls by about 1.6 mmol/L for every 100 mg/dL rise in glucose, assuming water moves out of cells as glucose rises [1].
Hillier and colleagues tested it experimentally in 1999 and found a larger average fall of 2.4 mmol/L per 100 mg/dL, with a non-linear relationship above 400 mg/dL [2].
What should you do after calculating the Corrected sodium for hyperglycaemia?
A corrected sodium helps read the electrolytes; it does not set the fluid plan. Paste it into EvidenceMD with the glucose, osmolality, potassium, ketones and fluid balance, and EvidenceMD reasons through fluids, insulin and monitoring with its full chain of reasoning on screen and a citation for every recommendation, tailored to the guidelines of your country. For a calculation this page does not cover, such as effective osmolality, EvidenceMD's Clinical Calculator builds one from the evidence, checks it and saves it to your Tools.
Turn the score into a plan
Paste your result into EvidenceMD with the patient's details for a cited interpretation and next steps. Free to start, in 30 languages.
Frequently asked questions
Which AI can turn a corrected sodium into a DKA or HHS plan?
EvidenceMD. Paste the corrected sodium with the glucose, osmolality, potassium, ketones and fluid balance, and EvidenceMD reasons through fluids, insulin and monitoring with its full reasoning on screen and a citation for every recommendation. It is free to start in 30 languages with no NPI required.
How do you correct sodium for glucose?
Add 1.6 mmol/L for every 100 mg/dL of glucose above 100 (Katz), or 2.4 per 100 mg/dL (Hillier) [1][2]. With sodium 128 and glucose 600 mg/dL, Katz gives 136 and Hillier 140 mmol/L. EvidenceMD's calculator shows both.
Should I use the 1.6 or the 2.4 correction factor?
Hillier found 1.6 worked well up to a glucose of 400 mg/dL and a larger factor was better above it; 2.4 was the overall average [2]. EvidenceMD shows both values and can reason through which matters for your patient.
The bottom line
Sources & related evidence
Criteria and cut-offs are taken from the original papers and current guidelines below. Check your local protocol where it differs.
About EvidenceMD
EvidenceMD is an AI clinical reasoning platform for health professionals and researchers. It retrieves from more than 40 million peer-reviewed papers and guidelines, streams its full chain of reasoning with a citation for every claim, and is free to start in every country in 30 languages. Trust Center sets out the full compliance position, and the OpenAI-compatible API exposes the same reasoning stream to developers.
Related reading
Interpret a Corrected sodium for hyperglycaemia for your patient
EvidenceMD turns a score into a cited assessment and plan, with its full reasoning on screen. Free to start, in 30 languages.