What Is Corrected Sodium?
Corrected sodium is a calculated estimate used when blood glucose is elevated. Hyperglycemia raises extracellular tonicity and draws water from cells into the extracellular fluid. That extra water can lower the measured serum sodium concentration even when total body sodium has not fallen in the same proportion.
The laboratory sodium is still the measured value. The corrected number estimates how sodium concentration might look after accounting for the glucose-related water shift. It belongs beside the original glucose, sodium, osmolality, kidney function, symptoms, and clinical history—not in place of them.
Corrected Sodium Formula for Hyperglycemia
Two correction factors are commonly discussed. Both equations require glucose in mg/dL and sodium in mEq/L:
1.6 mEq/L per 100 mg/dL2.4 mEq/L per 100 mg/dLThe calculator applies no negative correction when glucose is 100 mg/dL or lower. These equations were created to estimate the effect of hyperglycemia, not to adjust sodium downward during normal or low glucose.
How to Calculate Corrected Sodium
- 1
Use matching laboratory values
Copy measured serum sodium and glucose from the same blood draw. Do not combine results from different collection times.
- 2
Check the glucose unit
Select mg/dL or mmol/L. The calculator converts mmol/L glucose to mg/dL internally before applying the published equations.
- 3
Find glucose above 100
Subtract 100 mg/dL from glucose, then divide that difference by 100.
- 4
Apply both correction factors
Multiply by 1.6 for Katz and 2.4 for Hillier, then add each correction to measured sodium.
- 5
Keep both estimates in context
Compare the results with the original report and the method used by the treating team. Neither estimate determines treatment alone.
Corrected Sodium Calculation Example
- 1
Glucose above baseline: 500 − 100 = 400 mg/dL
- 2
Katz correction: 1.6 × (400 ÷ 100) = 6.4
- 3
Katz corrected sodium: 130 + 6.4 = 136.4 mEq/L
- 4
Hillier correction: 2.4 × (400 ÷ 100) = 9.6
- 5
Hillier corrected sodium: 130 + 9.6 = 139.6 mEq/L
The 3.2 mEq/L difference is not a calculator error. It comes from using two published correction factors. The clinical setting determines how an estimate is used.
Katz 1.6 vs Hillier 2.4 Correction Factors
Katz: 1.6
Adds 1.6 mEq/L for every 100 mg/dL rise in glucose above 100. It remains widely used and is adopted in several clinical discussions.
Classic coefficientHillier: 2.4
Hillier and colleagues found 2.4 mEq/L per 100 mg/dL was a better overall estimate in their controlled study.
Higher overall coefficientThe Hillier study also found the relationship was nonlinear: 1.6 performed reasonably through glucose of 400 mg/dL, while a larger correction fitted observations above 400. The study was small, and individual physiology varies. For transparency, this calculator shows the standard fixed 1.6 and 2.4 equations rather than silently switching to a third coefficient.
Corrected Sodium Calculator in mg/dL and mmol/L
U.S. laboratory reports usually show glucose in mg/dL. Other countries may report mmol/L. The conversion used by this calculator is:
For example, 27.75 mmol/L is approximately 500 mg/dL. Serum sodium is numerically the same in mmol/L and mEq/L because sodium carries one positive charge. Switching glucose units converts a populated glucose field without changing the sodium value.
How to Read a Glucose-Corrected Sodium Result
The concentration directly reported by the analyzer at that collection time.
An estimate after accounting for the glucose-associated water shift.
Requires trends, osmolality, volume status, kidney function, glucose, symptoms, and treatment context.
A result inside a common reference interval does not rule out illness, and an abnormal estimate does not identify its cause. Laboratory ranges also vary. Compare the result with the interval on the same report and with repeat measurements when a clinician orders them.
If acid-base status is part of the question, the Anion Gap Calculator answers a separate electrolyte calculation. Do not substitute one result for the other.
Important Limits and Common Errors
- Using values from different times: sodium and glucose can change quickly during illness and treatment.
- Mixing glucose units: entering mmol/L as mg/dL can produce a meaningless result.
- Applying a negative correction: the formula is intended for elevated glucose, not glucose below 100 mg/dL.
- Calling the result measured: corrected sodium is an estimate, while the laboratory sodium is measured.
- Confusing hypertonic hyponatremia with a lab artifact: glucose-related water shift is not the same mechanism as lipid- or protein-related pseudohyponatremia.
- Adding albumin: albumin is not an input to glucose-corrected sodium.
- Choosing treatment from the result: fluid selection, insulin, monitoring, and sodium correction rates require qualified clinical management.
When an Online Calculation Is Not Enough
Very high glucose and major sodium disturbances may occur during serious illness. Corrected sodium cannot diagnose diabetic ketoacidosis or hyperosmolar hyperglycemic state. Those conditions require symptoms, ketones, acid-base measurements, osmolality, hydration assessment, and other laboratory findings.
For blood-gas interpretation, use the ABG Calculator only as an educational arithmetic check while following appropriate clinical care.
Corrected Sodium Calculator FAQs
How do you calculate corrected sodium for hyperglycemia?
With glucose in mg/dL, Katz uses corrected Na = measured Na + 0.016 × (glucose − 100). Hillier uses the same structure with 0.024. This calculator reports both estimates.
Should I use 1.6 or 2.4 for sodium correction?
Katz uses 1.6 mEq/L per 100 mg/dL of glucose above 100. Hillier found 2.4 was a better overall estimate in a small controlled study. No fixed factor is exact for every person, so the tool shows both and labels the method.
Can I enter glucose in mmol/L?
Yes. Select mmol/L and enter the glucose value. It is converted to mg/dL internally before the equations are applied. Sodium stays numerically the same in mmol/L and mEq/L.
Why is corrected sodium higher than measured sodium?
Elevated glucose draws water from cells into extracellular fluid and can dilute the measured sodium concentration. The formula adds an estimated correction for that glucose-related shift.
Does albumin belong in the corrected sodium formula?
No. Glucose-corrected sodium uses measured sodium and glucose. Albumin is used in a separate corrected-calcium estimate.
Is corrected sodium the same as calculated serum osmolality?
No. Corrected sodium estimates one effect of hyperglycemia on sodium. Serum osmolality uses sodium, glucose, and usually BUN, with ethanol included in some formulas.
Can this calculator diagnose DKA or HHS?
No. It cannot diagnose either emergency or choose treatment. DKA and HHS require clinical assessment and additional laboratory measurements.
Evidence and Editorial Notes
The equations, unit handling, physiological explanation, and safety limits were checked against original research and current hyperglycemic-crisis literature.
- Katz MA. Hyperglycemia-induced hyponatremia—calculation of expected serum sodium depression. New England Journal of Medicine. 1973.
- Hillier TA, Abbott RD, Barrett EJ. Hyponatremia: evaluating the correction factor for hyperglycemia. American Journal of Medicine. 1999.
- Ing TS, et al. The Corrected Serum Sodium Concentration in Hyperglycemic Crises: Computation and Clinical Applications. Frontiers in Medicine. 2020.
- Umpierrez GE, et al. Hyperglycemic Crises in Adults With Diabetes: A Consensus Report. Diabetes Care. 2024.
- Chuang C, et al. Corrected sodium levels for hyperglycemia and clinical outcomes in extreme hyperglycemia. Journal of the Chinese Medical Association. 2020.
Last formula and source review: August 1, 2026. Calculations run in your browser. Values entered in this form are not sent to our server.