Sodium Correction Calculator

Sodium Correction Calculator. Enter your patient's serum sodium, serum glucose, and optionally select the correction formula to get the corrected sodium level in hyperglycemia. The calculator adjusts the measured sodium value to account for the osmotic effect of elevated glucose, helping you identify true hyponatremia or hypernatremia masked by high blood sugar. Also try the BUN to Creatinine Ratio Calculator.

Results

Corrected Serum Sodium

Sodium Correction Applied

Glucose Excess Above 100 mg/dL

Interpretation

Why do we need to correct sodium in hyperglycemia?

High blood glucose draws water out of cells into the bloodstream by osmosis, diluting the sodium concentration. The measured serum sodium will therefore appear falsely low. Correcting for glucose gives the true sodium level, which is essential for diagnosing and treating sodium disorders accurately. See also our Anion Gap Calculator.

What is the Katz correction formula?

The Katz formula adds 1.6 mEq/L to the measured sodium for every 100 mg/dL rise in glucose above a normal level of 100 mg/dL. It has been the traditional standard since 1973 and is widely used in clinical practice.

What is the Hillier correction formula and when should it be used?

The Hillier formula uses a correction factor of 2.4 mEq/L per 100 mg/dL glucose elevation instead of 1.6. Studies suggest this higher factor is more accurate when blood glucose exceeds 400 mg/dL, making it particularly relevant in diabetic ketoacidosis (DKA) and hyperosmolar hyperglycemic state (HHS).

What glucose level is considered 'normal' in this calculation?

The standard reference glucose used in both the Katz and Hillier formulas is 100 mg/dL. The correction is applied only to glucose levels above this threshold. Serum sodium does not need correction when glucose is within the normal range.

What does a corrected sodium above 145 mEq/L mean?

A corrected sodium above 145 mEq/L indicates true hypernatremia that was masked by the dilutional effect of hyperglycemia. This suggests significant free water deficit and requires prompt clinical evaluation and fluid management.

Can this calculator be used for hyponatremia evaluation?

Yes. If a patient appears hyponatremic but has elevated glucose, this calculator helps determine whether the low sodium is real or simply an artifact of hyperglycemia. A corrected sodium in the normal range (135–145 mEq/L) confirms pseudohyponatremia due to high glucose.

Is this calculator intended for clinical decision-making?

This tool is designed to support clinical calculations and should be used alongside full clinical assessment, laboratory results, and professional judgment. It does not replace physician evaluation or institutional guidelines.

What are the normal reference ranges for serum sodium?

Normal serum sodium is typically 135–145 mEq/L. Values below 135 mEq/L indicate hyponatremia, while values above 145 mEq/L indicate hypernatremia. The corrected sodium should be interpreted within this range in the context of the patient's clinical presentation. You might also find our Creatinine Clearance (Cockcroft-Gault) Calculator useful.