Hyperglycemia Sodium Correction Calculator

Estimates the corrected serum Na in patients with high glucose levels.

In the text below the tool there is more information about how the correction calculation is performed.


In patients diagnosed with hyperglycemia, sodium correction is necessary because serum Na levels may appear lower than they actually are.

This happens because hyperglycemia is associated with a temporary translational hyponatremia, that is caused by the migration of plasma glucose towards the cells.


The two formulas used are:

Corrected Sodium (Katz) = Measured sodium + 0.016 x (Serum glucose - 100)

Corrected Sodium (Hillier) = Measured sodium + 0.024 x (Serum glucose - 100)


Measured Sodium (Na):*
Serum Glucose:*
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Variables and formulas

There are two determinations required in order to calculate the sodium correction: the blood glucose value in either mg/dL, mmol/L or the other units from the list and the serum sodium measured in mEq/L.

The table below introduces the normal, low and high levels of serum sodium and glucose:

Determination Lower limit Normal range Higher limit
Sodium 80 136 - 145 200
Glucose 0 75 - 115 400

The correction is based on the formula created by Katz in 1973, where:

Corrected Sodium (Katz) = Measured sodium + 0.016 x (Serum glucose - 100)

This was revised by Hillier in 1999. His study found that the physiologic decrease in sodium concentration is considerably greater than the standard correction factor of 1.6 (meq/L Na per 100 mg/dL glucose), especially when the glucose concentration is greater than 400 mg/dL. Thus, a greater factor was considered.

Corrected Sodium (Hillier) = Measured sodium + 0.024 x (Serum glucose - 100)

 

Sodium correction explained

When looking at the test results of patients diagnosed with hyperglycemia, sodium levels need to be carefully analysed, to avoid confusion with hyponatremia.

The serum Na result can be altered by pre-existing high glucose levels and therefore needs to be corrected to reflect the real situation in the body.

During hyperglycemia, extra cellular fluid osmolality rises above that of intracellular fluid and thus glucose enters the cell, displacing water (back in the extracellular space).

This phenomenon translates in a depletion of cellular water and a serum Na concentration falling in proportion to the extra cellular fluid dilution. This decrease is said to be of 1.6 mEq/L for every 100 mg/dL increase in plasma glucose levels above normal.

The type of translational hyponatremia that occurs is not the classic hyponatremia because there is no real change in the total body water.

It was observed that once the glucose levels are lowered (by natural insulin mechanism or by external intervention), sodium levels also return to normal.

 

Original sources

1. Katz MA. Hyperglycemia-induced hyponatremia--calculation of expected serum sodium depression. N Engl J Med. 1973; 18;289(16):843-4.

2. Hillier TA, Abbott RD, Barrett EJ. Hyponatremia: evaluating the correction factor for hyperglycemia. Am J Med. 1999; 106(4):399-403.


App Version: 1.0.1

Coded By: MDApp

Specialty: Deficiency

System: Endocrine

Objective: Correction

Type: Calculator

No. Of Variables: 2

Year Of Study: 1973, 1999

Published On: August 20, 2017 · 07:10 AM

Last Checked: August 20, 2017

Next Review: August 20, 2018