Corrects the measured sodium for a high glucose with the Katz or Hillier factor, and shows whether a true sodium disorder remains.
Result
Enter the measured sodium and the glucose.
Sources
Hyperglycemic crises 2024 · 3 studies
Hyperglycemic crises 2024 expects sodium to rise 1.6 mmol/L per 100 mg/dL fall in glucose.
3
studies
525
citations
87
PubMed papers
Evidence
Guideline recommendation
“[A] reduction of 5.6 mmol/l [100 mg/dl] of glucose will result in a 1.6 mmol/l rise in sodium concentration. The initial rise in serum sodium is not an indication to give hypotonic fluids…”
Consensus report on hyperglycemic crises, 2024 (ADA, EASD, JBDS, AACE and DTS)
Diabetologia: Journal Metrics Score 7.8, Q1 · cited 181 times
PubMed · Free full text · DOI
Guideline recommendation
“Hyponatraemia, defined as a serum sodium concentration <135 mmol/l, is the most common disorder of body fluid and electrolyte balance encountered in clinical practice.”
European hyponatremia guideline, 2014 (ESICM, ESE and ERA-EDTA)
Nephrol Dial Transplant: Journal Metrics Score 1.2, Q2 · cited 602 times
Known limitations
In six healthy volunteers whose glucose was raised above 600 mg/dL and brought back down, sodium fell by a mean of 2.4 mmol/L per 100 mg/dL of glucose, more than the 1.6 commonly used (P = 0.02). The 1.6 factor worked up to 400 mg/dL; above it, 4.0 fitted better.
Calculated the expected depression of serum sodium from the water that moves out of cells as glucose rises: 1.6 mmol/L for each 100 mg/dL, the factor still used most often.
N Engl J Med: Journal Metrics Score 29.8, Q1 · cited 525 times
Two consecutive patients, one with hyperosmolar hyperglycemic state (measured sodium 112, corrected 167 mmol/L) and one with mixed HHS and DKA (149, corrected 177; both corrected with 2.4), developed osmotic demyelination although osmolality fell by only 1.2 and 1.0 mOsm/kg per hour. The authors conclude that severe hyperosmolality itself was the likely trigger, and that measured and corrected sodium should both be assessed.
Cureus · cited 1 times
PubMed · Free full text · DOI
The original paper has been cited 525 times, and 87 PubMed articles mention corrected sodium in their title or abstract. Citation counts from OpenAlex and article counts from PubMed, retrieved November 9, 2026. Journal Metrics Scores and quartiles are from this site’s current release; follow the journal name for details.
After the result
Below 135 after correction · 135 to 145 · Above 145 after correction
The glucose does not explain all of it: look for another cause. The low sodium is explained by the glucose. A hidden water deficit, as in hyperosmolar hyperglycemic state.
Next steps
Avoid common errors
6 common errors to avoid
and 4 more
When the correction misleads
1Which factor
The two factors can give results 10 mmol/L or more apart when glucose is very high: 112 mmol/L with glucose 2,398 mg/dL is 149 with 1.6 and 167 with 2.4. State the factor with the result.
2Glucose units
The formula uses glucose in mg/dL. A glucose of 60 entered as mg/dL instead of mmol/L gives no correction at all. Check the unit beside the box.
3Glucometer readings
Point-of-care meters often read only "High" above their range. Use the laboratory or blood gas glucose from the same sample as the sodium.
4Pseudohyponatremia
Severe hypertriglyceridemia or paraproteinemia lowers sodium measured by indirect electrodes while the sodium concentration in plasma water stays normal. This is a separate artifact, not corrected by the glucose formula.
5Other osmoles
Mannitol and other solutes that stay outside cells, such as glycine or sorbitol irrigation fluids, lower sodium in the same way as glucose; urea and alcohol do not. The glucose correction does not account for them.
6Not a treatment target
The corrected value describes the water balance now. Decisions on fluids follow the measured sodium, the osmolality and their trend, under the relevant protocol.
Formula
Sodium + 1.6 (or 2.4) × (glucose − 100) / 100, with glucose in mg/dL.
Na + 1.6 × (glucose − 100) / 100
Sodium + 1.6 (or 2.4) × (glucose − 100) / 100, with glucose in mg/dL.
Formula and ranges
| Factor | Corrected sodium (glucose in mg/dL) |
|---|---|
| Katz 1973 | sodium + 1.6 × (glucose − 100) / 100 |
| Hillier 1999 | sodium + 2.4 × (glucose − 100) / 100 |
| Result | mmol/L | Meaning |
|---|---|---|
| Low after correction | below 135 mmol/L | Below 135 mmol/L even after correction: a true hyponatremia that the glucose does not explain, so look for another cause. |
| Within the usual range | 135 to 145 mmol/L | Within the usual range of 135 to 145 mmol/L once corrected: any fall in the measured sodium is explained by the glucose. |
| High after correction | above 145 mmol/L | Above 145 mmol/L once corrected: a water deficit hidden by the glucose. The measured sodium will rise as the glucose falls. |
Katz 1973
Hillier 1999
Glucose below 100 mg/dL
Units
Test cases
4 published cases, each also a test case
4 published cases; the calculator reproduces every result.
Worked examples
A 13-year-old boy presented with new type 1 diabetes in a hyperosmolar hyperglycemic state. Sodium was 132 mmol/L with a glucose of 1,080 mg/dL (60 mmol/L). The report applies the 1.6 factor and gives a corrected sodium of approximately 148 mmol/L.
“Using a sodium correction factor of 1.6 mmol/L for each 100 mg/dL increase in glucose above 100 mg/dL, corrected sodium was approximately 148 mmol/L.”
The calculator gives 147.7 before rounding. A mildly low measured sodium of 132 hid a corrected value above 145.
Entered as: Measured sodium: 132 mmol/L (mEq/L); Glucose: 1080 mg/dL; Correction factor: 1.6 (Katz) (1.6).
Source: Alamer AT et al., Cureus 2026 (PubMed · Free full text · DOI)
A 52-year-old man with diabetes was obtunded after cocaine use, with a glucose of 1,655 mg/dL, venous pH 6.87 and a sodium of 125 mmol/L. The report gives a corrected sodium of approximately 150 mmol/L.
“sodium was 125 mmol/L (corrected sodium was approximately 150 mmol/L)”
The report does not name the factor; 1.6 reproduces it (149.9 before rounding), and 2.4 would give 162.
Entered as: Measured sodium: 125 mmol/L (mEq/L); Glucose: 1655 mg/dL; Correction factor: 1.6 (Katz) (1.6).
Source: Ibokette BG et al., Cureus 2026 (PubMed · Free full text · DOI)
A previously healthy 13-year-old boy with new type 1 diabetes had a glucose of 1,029 mg/dL and a sodium of 123 mmol/L. The report gives a corrected sodium of 145 mmol/L.
“serum sodium of 123 mmol/L (corrected sodium, 145 mmol/L)”
The report does not name the factor; 2.4 reproduces it (145.3 before rounding), while 1.6 would give 138.
Entered as: Measured sodium: 123 mmol/L (mEq/L); Glucose: 1029 mg/dL; Correction factor: 2.4 (Hillier) (2.4).
Source: García-Sánchez P et al., Cureus 2026 (PubMed · Free full text · DOI)
A 58-year-old woman with untreated hyperglycemia was unresponsive (GCS E1V1M1), with a glucose of 2,398 mg/dL, a measured sodium of 112 mmol/L and an osmolality of 387 mOsm/kg. The report gives a corrected sodium of 167 mmol/L; she later developed osmotic demyelination.
“her "corrected sodium" was calculated as 167 mmol/L, indicating hypernatremia”
Case 1 of the report. The 2.4 factor reproduces 167 (167.2 before rounding); 1.6 would give 149. Profound measured hyponatremia here was in fact hypernatremia.
Entered as: Measured sodium: 112 mmol/L (mEq/L); Glucose: 2398 mg/dL; Correction factor: 2.4 (Hillier) (2.4).
Source: Kasamatsu D et al., Cureus 2025 (PubMed · Free full text · DOI)
FAQ
7 questions and answers
and 5 more answers
Questions
Corrected sodium = measured sodium + 1.6 × (glucose − 100) / 100, with sodium in mmol/L (mEq/L) and glucose in mg/dL. This is the Katz factor of 1.6; Hillier and colleagues proposed 2.4 instead. With glucose in mmol/L, multiply it by 18 first, or use 1.6 × (glucose − 5.6) / 5.6.
Take the glucose above 100 mg/dL, divide by 100 and multiply by the factor, then add it to the measured sodium. A sodium of 132 mmol/L with a glucose of 1,080 mg/dL gives 132 + 1.6 × 980 / 100 = 132 + 15.7 = 147.7, so the corrected sodium is 148 mmol/L.
Both are in use. 1.6 (Katz 1973) is the traditional factor and the one the 2024 consensus report on hyperglycemic crises describes. Hillier and colleagues measured a mean fall of 2.4 mmol/L per 100 mg/dL in healthy volunteers, and found 1.6 adequate up to about 400 mg/dL but too small above it. The calculator shows both, so you can see how much the choice matters for your patient.
Glucose stays outside cells when insulin is lacking, so it draws water out of the cells into the blood and dilutes the sodium. This is a true fall in sodium concentration with a high, not low, serum osmolality, sometimes called translocational hyponatremia. As the glucose falls, water moves back and the sodium rises.
No. Pseudohyponatremia is a laboratory artifact: very high lipids or proteins take up plasma volume and make indirect electrode methods read the sodium too low, while the sodium in plasma water is normal. Hyperglycemia causes a real dilution. A blood gas analyzer, which uses a direct electrode, is not affected by lipids or protein but still shows the dilution from glucose.
A corrected sodium above 145 mmol/L means the patient has lost more water than sodium, a deficit that the glucose is hiding. It is common in hyperosmolar hyperglycemic state. The measured sodium is expected to rise as the glucose falls; the 2024 consensus report notes that this rise on its own is not an indication to give hypotonic fluids.
Yes; the calculator converts it. 100 mg/dL is 5.6 mmol/L, so the 1.6 factor is 1.6 mmol/L of sodium for every 5.6 mmol/L of glucose above 5.6, or about 0.29 per mmol/L.
Further reading
8 references with PubMed and DOI links
8
references
5
free full text
From Katz MA, N Engl J Med 1973 to the newest case reports.
References
Contributed by Dr. Meng Zhao (MD · Former Neurosurgeon · Medical AI Researcher), from the original publications listed here. Last updated November 6, 2026. LinkedIn
The calculator code is tested against every worked example on this page before each release.
This calculator supports, and does not replace, clinical judgment. It is meant for healthcare professionals and is not medical advice for patients. Report an error through the contact page.
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Which also published the 2024 consensus on hyperglycemic crises, with its current metrics.