Corrected Sodium in Hyperglycemia

Methodology

Katz (1973); Hillier (1999)

corrected Na = Na + factor × (glucose − 100) ÷ 100; factor 1.6 (Katz) or 2.4 (Hillier)

Hillier's experiment found an overall factor of 2.4 mmol/L per 100 mg/dL rise in glucose; 1.6 fitted well up to about 400 mg/dL and about 4.0 above it. The 2009 ADA consensus used 1.6.

Who it is for

Adults with hyperglycaemia (e.g. DKA, HHS).

Version

1.1.0

How this calculator works

Where the formula comes from

• Katz (1973) proposed a fall of 1.6 mmol/L in sodium for every 100 mg/dL rise in glucose, based on a theoretical calculation rather than measurements in patients.^[1]
• Hillier and colleagues (1999) tested the relationship in 6 healthy volunteers whose glucose was raised above 600 mg/dL with dextrose while insulin secretion was suppressed with somatostatin.^[2]
• In that study sodium fell by an average of 2.4 mmol/L per 100 mg/dL rise in glucose, more than the 1.6 factor.^[2]

The inputs

• The correction applies to glucose above 100 mg/dL: corrected sodium = measured sodium + factor × (glucose − 100) ÷ 100.^[1][2]

Versions and alternatives

• Hillier's data were non-linear: a factor of 1.6 fitted well up to about 400 mg/dL, while about 4.0 fitted better above 400 mg/dL.^[2]

Where accuracy falls (published evidence)

• The 2.4 factor comes from 6 healthy volunteers with induced hyperglycaemia, not from patients with diabetic ketoacidosis or hyperosmolar states.^[2]
• Corrected sodium changes during treatment with shifts in water, sodium and potassium, so it needs to be recalculated from repeated measurements.^[3]

What guidelines say

• The 2009 American Diabetes Association consensus on hyperglycaemic crises uses corrected sodium, with the 1.6 factor, to help choose between 0.9% and 0.45% saline.^[4]

Sources

1. Katz MA. Hyperglycemia-induced hyponatremia—calculation of expected serum sodium depression. N Engl J Med. 1973;289(16):843–844. doi:10.1056/NEJM197310182891607
2. Hillier TA, Abbott RD, Barrett EJ. Hyponatremia: evaluating the correction factor for hyperglycemia. Am J Med. 1999;106(4):399–403. doi:10.1016/S0002-9343(99)00055-8
3. Ing TS, Ganta K, Bhave G, et al. The corrected serum sodium concentration in hyperglycemic crises: computation and clinical applications. Front Med (Lausanne). 2020;7:477. doi:10.3389/fmed.2020.00477
4. Kitabchi AE, Umpierrez GE, Miles JM, Fisher JN. Hyperglycemic crises in adult patients with diabetes. Diabetes Care. 2009;32(7):1335–1343. doi:10.2337/dc09-9032

Compiled from the published sources above. Every statement was agreed independently by three AI research tools (Claude, ChatGPT, DeepSeek) and its source verified in PubMed or Crossref by the Hakeemly editorial team. Not reviewed by a doctor unless stated. Agreed on 2026-10-11

Worked example: how to calculate corrected sodium

An illustration with sample values, worked out with the same method the tool above uses.

Limitations

• An estimate; follow trends in measured sodium during treatment.

References

1. Katz MA. Hyperglycemia-induced hyponatremia—calculation of expected serum sodium depression. N Engl J Med. 1973;289(16):843–844. doi:10.1056/NEJM197310182891607
2. Hillier TA, Abbott RD, Barrett EJ. Hyponatremia: evaluating the correction factor for hyperglycemia. Am J Med. 1999;106(4):399–403. doi:10.1016/S0002-9343(99)00055-8
3. Kitabchi AE, Umpierrez GE, Miles JM, Fisher JN. Hyperglycemic crises in adult patients with diabetes. Diabetes Care. 2009;32(7):1335–1343. doi:10.2337/dc09-9032