Corrected Sodium (Hyperglycaemia)

Sodium Resolver

Hyperglycaemic Offset

Primary Inputs

Measured Sodium (Na)

Glucose (mg/dL)

Osmotic Flux

Enter sodium and glucose to calculate the corrected sodium level.

Guidelines & Evidence

Verified

Last Review: 2026-07-17

When to Use

What is Corrected Sodium (Hyperglycemia Correction)?

Corrected sodium (also called glucose-corrected sodium or Katz correction) is a calculated value that estimates the "true" serum sodium concentration in patients with hyperglycemia (elevated blood glucose). Glucose is an osmotically active solute. When blood glucose rises significantly (typically >200-300 mg/dL, >11-17 mmol/L), water is drawn from the intracellular space (inside cells) into the extracellular space (bloodstream) due to the osmotic gradient. This dilutes serum sodium, causing a factitious (or "dilutional") hyponatremia. The corrected sodium calculation estimates what the sodium concentration would be if the glucose were normal (e.g., 100 mg/dL or 5.6 mmol/L). This value is critical for guiding fluid management in diabetic emergencies: if the corrected sodium is low, the patient has true hyponatremia (total body water excess relative to sodium); if the corrected sodium is high or normal, the patient is water-depleted (despite a low measured sodium), and hypotonic fluids (0.45% NaCl) may be appropriate.

Primary Clinical Indications

Diabetic Ketoacidosis (DKA) – All patients with DKA and glucose >250 mg/dL should have corrected sodium calculated to guide fluid selection (0.9% vs 0.45% NaCl) and assess true sodium status

Hyperosmolar Hyperglycemic State (HHS) – Essential for fluid management in HHS, where glucose is often >600 mg/dL and sodium may be factitiously low (or normal) despite profound water depletion

Pediatric DKA (cerebral edema prevention) – Failure to correct sodium may lead to inappropriate fluid choices (e.g., 0.45% NaCl when corrected sodium is normal or high, risking too-rapid correction of hyperosmolality). Monitoring corrected sodium trend helps guide when to add dextrose to IV fluids

Management of severe hyperglycemia in hospitalized patients – Any patient with glucose >300 mg/dL (e.g., steroid-induced hyperglycemia, stress hyperglycemia, TPN-related) should have corrected sodium calculated before diagnosing hyponatremia

Differentiating true from dilutional hyponatremia – If measured sodium is low (e.g., 125 mEq/L) but glucose is elevated (e.g., 600 mg/dL), corrected sodium may be 130-135 mEq/L (normal), indicating factitious hyponatremia. True hyponatremia requires different management (fluid restriction, vasopressin antagonists)

Monitoring response to insulin therapy – As glucose falls with insulin, water shifts back into cells, and measured sodium should rise. A failure of measured sodium to rise (or a paradoxical fall) indicates worsening true hyponatremia or excessive free water administration

Assessing risk of cerebral edema (pediatric DKA) – A rise in corrected sodium >3 mEq/L over 4 hours (or >12 mEq/L over 24 hours) is associated with increased risk of cerebral edema. Serial corrected sodium measurements guide fluid adjustment

Contraindications / Limitations

Not valid in severe hyperlipidemia or hyperproteinemia – Pseudohyponatremia (from lipids or paraproteins) coexisting with hyperglycemia confounds interpretation. Ionized sodium (direct ISE) is preferred.

Not valid in severe renal failure (oliguria) – The correction formula assumes normal renal handling of water; in oliguric renal failure, free water excretion is impaired, and the dilutional effect may be attenuated or prolonged.

Not a substitute for clinical assessment – Corrected sodium is an estimate. Some studies suggest it may overcorrect or undercorrect in individual patients. Use with clinical judgment.

Correction factor depends on glucose level – The classic 1.6 factor (Katz) was derived from studies with glucose <600 mg/dL. For glucose >600 mg/dL, Hillier suggests a higher factor (2.4). For glucose <200 mg/dL, correction is not needed (dilutional effect negligible).

Assumes normal serum osmolality relationship – In HHS, serum osmolality is often >320 mOsm/kg. The correction formula is still valid but must be interpreted alongside osmolality and neurological status.

Not applicable for chronic hyperglycemia – In poorly controlled diabetes with chronic glucose elevation (e.g., 200-300 mg/dL for weeks), the osmotic shift reaches equilibrium, and the correction factor may differ (chronic adaptation). Use caution in non-acute settings.

Comparison of Correction Factors (Katz vs Hillier vs Others)

Author/Year	Correction Factor	Glucose Range	Population	Clinical Use
Katz (1973)	1.6 mEq/L Na decrease per 100 mg/dL glucose increase above 100 mg/dL	Any hyperglycemia (derived from studies with glucose <600 mg/dL)	General medical inpatients	Most widely used; simple, single factor. Suitable for most clinical settings.
Hillier (1999)	Varies: 2.4 mEq/L per 100 mg/dL for glucose >400 mg/dL; 2.0 mEq/L per 100 mg/dL for glucose 200-400 mg/dL	Up to 1,500 mg/dL	65 hyperglycemic patients (DKA, HHS, other)	More accurate at very high glucose (>400 mg/dL). Preferred in HHS and severe DKA.
Moran & Jamison (1978)	1.6 mEq/L (same as Katz)	Limited range	Not widely used	Historical; same as Katz.
Turchin (2005)	1.6 mEq/L (validated in large cohort)	Mean glucose 415 mg/dL (range 200-1,200)	12,000+ hospitalized patients (retrospective)	Confirmed Katz factor in large dataset; no need for adjustment based on renal function?
Pediatric DKA (ISPAD)	1.6 mEq/L (Katz) OR 1.6/3? Actually ISPAD uses 1.6	Pediatric DKA	Children	Same as Katz; monitor trend (rise of 3 mEq/L in 4 hours predicts cerebral edema)
UK Joint British Diabetes Societies (JBDS)	1.5-2.0 mEq/L (range), often uses 1.6	DKA and HHS	Adult inpatients	Recommends Katz; also recommends monitoring measured sodium rise (should increase as glucose falls)

How it Works

Standard Corrected Sodium Formula (Katz 1973)

Corrected Na (mEq/L) = Measured Na + 1.6 × (Glucose (mg/dL) - 100) / 100 OR (simplified): Corrected Na = Measured Na + 0.016 × (Glucose - 100) Where: • Measured Na = serum sodium (mEq/L) • Glucose = serum glucose (mg/dL) • 1.6 = correction factor (mEq/L Na decrease per 100 mg/dL glucose increase above 100) • 100 = normal glucose baseline (mg/dL) Example: Glucose 600 mg/dL, Measured Na 125 mEq/L → Corrected Na = 125 + 1.6 × (600-100)/100 = 125 + 1.6 × 5 = 125 + 8 = 133 mEq/L Interpretation: The patient's true sodium (if glucose were normal) is 133 mEq/L (mild hyponatremia), not 125 mEq/L (moderate). This guides fluid choice (likely 0.9% NaCl initially).

Alternative Formula (Hillier 1999, Glucose >400 mg/dL)

For glucose >400 mg/dL: Corrected Na = Measured Na + 2.4 × (Glucose - 100) / 100 For glucose 200-400 mg/dL: Corrected Na = Measured Na + 2.0 × (Glucose - 100) / 100 Example (HHS): Glucose 1000 mg/dL, Measured Na 140 mEq/L → Corrected Na = 140 + 2.4 × (1000-100)/100 = 140 + 2.4 × 9 = 140 + 21.6 = 161.6 mEq/L (severe hypernatremia, profound water depletion)

Interpretation of Corrected Sodium in Hyperglycemia

Corrected Sodium Range	Interpretation	Fluid Management Implication	Key Action
<135 mEq/L	True hyponatremia (total body water excess relative to sodium, despite hyperglycemia)	Patient may be volume overloaded (heart failure, cirrhosis, SIADH) or have severe true sodium deficit. Use 0.9% NaCl (normal saline) or even hypertonic saline (3%) if severe (<120 mEq/L with neurological symptoms). Avoid 0.45% NaCl (hypotonic).	Check volume status, consider underlying cause of true hyponatremia (SIADH, heart failure, adrenal insufficiency). Monitor closely for overcorrection.
135-145 mEq/L	Normonatremia (true sodium normal; measured low due to dilution only)	Patient is eunatremic. Use 0.9% NaCl initially (resuscitation) then transition to 0.45% NaCl once glucose <250 mg/dL and corrected sodium stable.	Standard DKA/HHS protocol. Monitor measured sodium rise as glucose falls (should increase).
>145 mEq/L	True hypernatremia (free water deficit, severe volume depletion)	Patient is water-depleted. Use 0.45% NaCl (hypotonic) initially to correct free water deficit. Avoid 0.9% NaCl (may worsen hypernatremia by adding sodium without enough water).	Calculate free water deficit (0.6 × weight in kg × [serum Na/140 - 1]). Replace deficit over 48 hours. Monitor corrected sodium trend.
>160 mEq/L (HHS)	Severe hypernatremia, massive free water deficit	Use 0.45% NaCl (hypotonic) or 0.9% NaCl if hypotensive, but transition to hypotonic as soon as hemodynamically stable. Consider enteral water (NG) if possible.	Replace free water deficit slowly (8-12 mEq/L per day maximum correction). Risk of cerebral edema if overcorrected too rapidly.

Expected Rise in Measured Sodium as Glucose Falls (DKA/HHS)

Time Period	Expected Change in Measured Na	Clinical Significance	Action if Change Exceeds Range
First 4 hours of insulin/fluids	Increase of 1-2 mEq/L (mild rise)	Normal response; water shifts back into cells as glucose is metabolized/in excreted.	If no rise or decrease, suspect: (1) Too much free water (hypotonic fluids), (2) Continuing water loss (osmotic diuresis from glucose), (3) True hyponatremia (adrenal insufficiency, SIADH). Adjust fluid type (reduce free water).
Over 24 hours	Total increase of 4-8 mEq/L	Sodium should trend toward corrected sodium value as glucose normalizes.	If measured Na rises too fast (>12 mEq/L in 24 hours), risk of cerebral edema (especially children). Slow fluid rate, consider adding dextrose (D5 0.45% NaCl) to prevent too-rapid glucose fall.
In children (DKA)	Increase of ≤3 mEq/L in first 4 hours (ISPAD guideline)	Rise >3 mEq/L in 4 hours associated with increased cerebral edema risk.	If rise >3 mEq/L, slow IV fluid rate, consider adding dextrose, notify PICU. Perform neurological exam q1h.
In HHS (very high glucose)	May rise 10-20 mEq/L over 24 hours (free water deficit correction)	Expected, as fluid deficit is replaced (using 0.45% NaCl or 0.9% NaCl with enteral water).	Monitor neurological status (confusion, lethargy, coma). Avoid too-rapid correction of hyperosmolality (target decrease of 3-8 mOsm/kg/hour).

Clinical Pearls

Critical Pearl #1: Use Corrected Sodium to Guide Fluid Selection, Not Measured Sodium

In DKA/HHS, the measured sodium is artificially low due to dilution. Relying on measured sodium leads to inappropriate fluid choices. Example: A patient with DKA has glucose 600 mg/dL, measured Na 125 mEq/L. Corrected Na = 133 mEq/L (normal). If you used measured Na, you might think the patient is hyponatremic and give 0.9% NaCl (which is appropriate for true hyponatremia). However, in this case, 0.9% NaCl is still appropriate (but for different reasons: the patient needs volume resuscitation, and 0.9% NaCl is the standard initial fluid). But where corrected Na changes management: Another patient with glucose 600 mg/dL, measured Na 135 mEq/L. Corrected Na = 135 + 8 = 143 mEq/L (mild hypernatremia, water depleted). If you used measured Na (135, normal), you might use 0.9% NaCl. However, 0.45% NaCl would be better (adds free water to correct hypernatremia). Action: Calculate corrected Na in every patient with glucose >200 mg/dL before selecting IV fluids. For corrected Na <135, 0.9% NaCl is appropriate. For corrected Na >145, consider 0.45% NaCl (if hemodynamically stable) or add enteral water. For corrected Na 135-145, 0.9% NaCl initially, then 0.45% NaCl after glucose <250 mg/dL.

Critical Pearl #2: In DKA, Measured Na Should Rise as Glucose Falls

As insulin and fluids are administered, glucose decreases. Water shifts back into cells, and measured sodium should increase toward the corrected sodium value. Normal response: Glucose 600 → 200 mg/dL, measured Na 125 → 131 mEq/L (increase of 6 mEq/L). Corrected Na may decrease slightly (from 133 to 131), but that is normal. Abnormal response (measured Na fails to rise or falls): Indicates (1) Excess free water administration (using 0.45% NaCl when 0.9% NaCl needed), (2) Ongoing osmotic diuresis (glucose still >300 mg/dL, high urine output), (3) True hyponatremia unmasked (adrenal insufficiency, SIADH, heart failure). Action in pediatric DKA (cerebral edema prevention): The ISPAD guideline recommends that if measured Na rises >3 mEq/L in the first 4 hours, slow the IV fluid rate (reduce from 1.5x maintenance to 1.0x maintenance) and consider adding dextrose to fluids (to prevent too-rapid glucose fall). A rise of >3 mEq/L in 4 hours is a risk factor for cerebral edema (though not universally predictive).

Critical Pearl #3: For Glucose >400 mg/dL, Consider Hillier Factor (2.4) for Accuracy

The classic Katz factor (1.6) underestimates the true sodium at very high glucose levels (>400 mg/dL). Hillier (1999) demonstrated that the relationship between glucose and sodium is non-linear: at glucose >400 mg/dL, each 100 mg/dL increase decreases sodium by 2.4 mEq/L (not 1.6). Example: HHS patient, glucose 1000 mg/dL, measured Na 140 mEq/L. - Katz corrected Na = 140 + 1.6×9 = 140 + 14.4 = 154.4 mEq/L - Hillier corrected Na = 140 + 2.4×9 = 140 + 21.6 = 161.6 mEq/L The Hillier value (161.6) indicates more severe water depletion, guiding more aggressive free water replacement (0.45% NaCl, enteral water). Recommendation: For glucose 200-400 mg/dL, use 1.6-2.0 factor. For glucose >400 mg/dL, use 2.4 factor. For glucose >800 mg/dL (HHS), strongly consider Hillier (2.4).

Critical Pearl #4: Corrected Sodium Helps Predict Risk of Cerebral Edema in Pediatric DKA

Cerebral edema is the most feared complication of pediatric DKA, occurring in 0.5-1% of episodes, with 20-40% mortality. The corrected sodium (and its trend) is one of several risk factors (others include: new-onset diabetes, age <5 years, severe acidosis pH <7.1, high BUN, severe hypocapnia, treatment with bicarbonate). Specific corrected sodium thresholds: - A rise in measured sodium of >3 mEq/L within the first 4 hours of treatment is associated with increased cerebral edema risk (ISPAD guideline). This rise reflects rapid fluid shifts and osmotic changes. - Corrected sodium that remains low (<135 mEq/L) despite initial fluid resuscitation may indicate true hyponatremia (from SIADH or adrenal insufficiency), which also increases cerebral edema risk. Action: In pediatric DKA, monitor corrected sodium q2h for first 6-8 hours. If measured Na rises >3 mEq/L in 4 hours: (1) Slow IV fluid rate, (2) Add dextrose to fluids (D5 0.9% NaCl or D5 0.45% NaCl) to prevent too-rapid glucose fall, (3) Perform neurological exam q1h (check for headache, vomiting, change in consciousness, Cushing triad, pupillary changes). If cerebral edema suspected (headache, seizures, altered mental status, hypertension, bradycardia, abnormal respirations): Give mannitol 0.5-1 g/kg IV or hypertonic saline (3%) 2.5-5 mL/kg over 10-15 minutes, transfer to ICU, hyperventilate (pCO2 28-32), consider head CT.

Common Pitfalls in Corrected Sodium Use

Using corrected sodium when glucose is normal or only mildly elevated (<200 mg/dL) – No correction needed (dilutional effect negligible). Correction may produce spurious values.

Assuming all hyponatremia in hyperglycemia is dilutional – Hyperglycemia can unmask true hyponatremia (e.g., adrenal insufficiency). If corrected sodium is <130 mEq/L, suspect underlying true hyponatremia. Check cortisol, TSH, volume status.

Relying on measured sodium alone in HHS – In HHS, measured sodium may be normal or even high, but corrected sodium (using Hillier factor) often reveals profound hypernatremia (150-170 mEq/L). Failing to correct leads to inadequate free water replacement.

Using only 0.9% NaCl in HHS with corrected hypernatremia – 0.9% NaCl has Na 154 mEq/L, Cl 154 mEq/L, which is slightly hypertonic. In severe hypernatremia (corrected Na >160), 0.45% NaCl (Na 77 mEq/L) is preferred (adds free water). Use 0.9% NaCl only if hypotensive (needs volume resuscitation).

Ignoring the trend of corrected sodium – A falling corrected sodium as glucose improves suggests administration of excessive free water (using 0.45% NaCl when 0.9% NaCl needed) or development of true hyponatremia. Adjust fluid type.

Using corrected sodium to guide potassium replacement – Corrected sodium does NOT affect potassium management (hypokalemia is common in DKA due to osmotic diuresis, insulin-induced shift, and total body deficit). Follow potassium protocols separately.

Forgetting to re-calculate corrected sodium as glucose changes – Corrected sodium should be re-calculated with each glucose measurement (typically q1-2h in DKA). Using an outdated corrected sodium value misguides ongoing fluid management.

Using the Katz factor in very high glucose (>800 mg/dL) and hyperosmolar state – Likely underestimates true sodium. Use Hillier factor (2.4) for better accuracy.

Confusing corrected sodium for measured sodium in clinical documentation – Always specify "corrected sodium" when documenting calculated values. Document both measured and corrected in the medical record to avoid confusion.

Fluid Management Algorithm Based on Corrected Sodium

Corrected Sodium	Initial Fluid (First 1-2 hours)	Subsequent Fluid (After Glucose <250 mg/dL)	Special Considerations
<135 mEq/L (true hyponatremia)	0.9% NaCl (normal saline) bolus 10-20 mL/kg if hypotensive, then 250-500 mL/hr (adults). Avoid hypotonic fluids.	0.9% NaCl with potassium. Consider adding D5 after glucose <250 to prevent too-rapid glucose fall. Evaluate for adrenal insufficiency, SIADH, heart failure.	If severe (<120 mEq/L with neurological symptoms), consider 3% hypertonic saline (slow, monitored). Check cortisol urgently.
135-145 mEq/L (normonatremia)	0.9% NaCl (standard DKA/HHS protocol). Bolus 10-20 mL/kg if hypotensive (HHS often needs more).	Switch to 0.45% NaCl with potassium once glucose <250 mg/dL (adults) or <300 mg/dL (children) to provide free water and prevent too-rapid glucose fall.	Monitor measured Na rise; if increases >3 mEq/L in 4 hours (pediatric), slow rate, add dextrose earlier.
>145 mEq/L (true hypernatremia, water depletion)	0.9% NaCl if hypotensive (briefly). If euvolemic or hypervolemic, use 0.45% NaCl (hypotonic).	0.45% NaCl with potassium. Add D5 when glucose <250 to prevent hypoglycemia and provide free water. Consider enteral water (via NG) if alert and able to swallow.	Calculate free water deficit: Total body water (0.6× weight in kg) × (serum Na/140 - 1). Replace deficit over 48 hours (1/2 in first 24 hours). Avoid 0.9% NaCl (worsens hypernatremia).

Next Steps

Step-by-Step Clinical Action Based on Corrected Sodium

Calculating Free Water Deficit in HHS with Hypernatremia

Free Water Deficit (L) = Total Body Water (L) × (Serum Na / 140 – 1) Where Total Body Water (TBW) = 0.6 × weight (kg) for men, 0.5 × weight (kg) for women, 0.5 × weight for elderly, 0.6 × weight for children. Example: HHS patient, male, weight 80 kg, corrected Na 165 mEq/L (using Hillier factor). TBW = 0.6 × 80 = 48 L Free Water Deficit = 48 × (165/140 - 1) = 48 × (1.1786 - 1) = 48 × 0.1786 = 8.6 L deficit Replace deficit over 48 hours: 4.3 L free water in first 24 hours (plus maintenance fluids). Use 0.45% NaCl (which is 77 mEq/L Na, providing free water). Enteral water (via NG or oral) is more effective and safer (0.45% NaCl adds both Na and Cl). For every 1 L of enteral water, provides 1 L free water; 1 L of 0.45% NaCl provides 0.5 L free water + 0.5 L isotonic NaCl.

Sample Clinical Documentation for Corrected Sodium Cases

Example 1: DKA with corrected sodium normal: "Patient is a 28-year-old male with type 1 diabetes presenting with DKA (glucose 550 mg/dL, measured Na 128 mEq/L, K 4.5, Cl 95, HCO₃ 12, pH 7.20, β-hydroxybutyrate 6.5). Corrected sodium (Katz) = 128 + 1.6 × (550-100)/100 = 128 + 1.6 × 4.5 = 128 + 7.2 = 135.2 mEq/L (normonatremia). Plan: 0.9% NaCl at 500 mL/hr x 4 hours, then reassess. Insulin drip 0.1 U/kg/hr. Potassium replacement (20 mEq/L in fluids). Monitor corrected sodium q2h. Glucose target decline 50-75 mg/dL/hour." Example 2: HHS with corrected hypernatremia (Hillier factor): "Patient is a 65-year-old female with type 2 diabetes, HHS (glucose 1,200 mg/dL, measured Na 142 mEq/L, K 4.2, Cl 100, HCO₃ 24, pH 7.38, osmolality 365 mOsm/kg). Corrected sodium (Hillier, glucose >400) = 142 + 2.4 × (1200-100)/100 = 142 + 2.4 × 11 = 142 + 26.4 = 168.4 mEq/L (severe hypernatremia, massive free water deficit). Free water deficit (female, 70 kg, TBW 0.5 × 70 = 35 L) = 35 × (168.4/140 - 1) = 35 × (1.203 - 1) = 35 × 0.203 = 7.1 L. Plan: 0.45% NaCl at 500 mL/hr x 4 hours (provides 250 mL free water per hour). Assess volume status (patient is hypotensive, SBP 90, so 0.9% NaCl 1 L bolus given first, then switch to 0.45% NaCl). Enteral water via NG tube 100 mL/hour (safe if alert, no aspiration risk). Goal: decrease corrected Na by <10 mEq/L in first 24 hours, free water deficit replaced over 48 hours. Monitor neurological status q1h (risk of cerebral edema if overcorrection)." Example 3: Pediatric DKA with monitored corrected sodium trend: "Patient is a 9-year-old female, new-onset type 1 diabetes, DKA (glucose 450 mg/dL, measured Na 130 mEq/L, weight 30 kg). Corrected Na (Katz) = 130 + 1.6 × (450-100)/100 = 130 + 1.6 × 3.5 = 130 + 5.6 = 135.6 mEq/L (normonatremia). Plan per ISPAD: IV fluids 0.9% NaCl with potassium at 1.5x maintenance (1950 mL/m²/day, approx 1200 mL/day). Corrected sodium q2h: 2h: 132 (+2), 4h: 133 (+3), 6h: 132 (stable). At 4h, measured Na rose 3 mEq/L (threshold for concern). Slowed IV rate to 1.0x maintenance (800 mL/day), added D5 to fluids (D5 0.45% NaCl). Neurological exam q1h: alert, no headache, no vomiting. Glucose fell from 450 to 220 mg/dL appropriately. No cerebral edema developed. Transitioned to subcutaneous insulin when glucose <250 and anion gap closed."

Origins & History

Katz and the Birth of Corrected Sodium

Dr. Murray A. Katz (1932-2013) was a nephrologist at the University of Texas Medical Branch (UTMB) in Galveston, Texas. In 1973, he published a one-page letter in the New England Journal of Medicine titled "Hyperglycemia-induced hyponatremia: calculation of expected serum sodium concentration." In this letter, he derived the formula using basic physiological principles: Plasma osmolality = 2 × Na + Glucose/18. Assuming normal osmolality (290 mOsm/kg), he solved for Na. The resulting equation gave a correction factor of 1.6 mEq/L Na decrease per 100 mg/dL glucose increase above 100 mg/dL. This simple formula became standard practice in the management of DKA and HHS. For decades, it was taught to medical students and residents worldwide. Despite later refinements (Hillier 1999 showing higher factors at very high glucose), the Katz formula remains the most widely used, due to its simplicity and adequacy in most clinical situations.

Key Contributors and Timeline

Year	Contributor(s)	Institution	Contribution
1973	Katz MA	University of Texas Medical Branch, Galveston, TX	Derivation of correction factor (1.6 mEq/L per 100 mg/dL glucose). NEJM letter.
1978	Moran SM, Jamison RL	Stanford University	Validation of Katz factor in small cohort.
1999	Hillier TA, Abbott RD, Barrett EJ	University of Virginia, Charlottesville, VA	Refinement: non-linear correction (2.0 for glucose 200-400, 2.4 for >400). Am J Med paper.
2005	Turchin A, Matheny ME, Shubina M, et al.	Brigham and Women's Hospital, Boston, MA	Large validation (12,000+ patients) comparing Katz and Hillier; both have utility depending on glucose level.
2006	American Diabetes Association (ADA) Guidelines	ADA	First inclusion of corrected sodium in DKA/HHS management algorithms.
2018	ISPAD Guidelines (Wolfsdorf JI, et al.)	International Society for Pediatric and Adolescent Diabetes	Formal recommendation for corrected sodium monitoring in pediatric DKA with specific thresholds for cerebral edema prevention.
2023	JBDS DKA Guidelines (UK)	Joint British Diabetes Societies	Recommend corrected sodium using Katz factor (1.6) for DKA; emphasize trend over single value.

Future Directions

The corrected sodium remains a cornerstone of DKA/HHS management. However, emerging evidence suggests that direct measurement of serum osmolality and calculation of the sodium-glucose ratio may be more accurate in individual patients. Point-of-care osmolality meters (freezing point depression) can rapidly measure osmolality; comparing measured osmolality to calculated (2Na + Glucose/18) can identify unmeasured osmoles (ethanol, mannitol, toxic alcohols) but also provides a more precise sodium correction. Nevertheless, the Katz formula (1.6) is likely to remain in use for decades due to its simplicity and adequate performance in most clinical settings.

Last Comprehensive Review: 2026-07-17

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Author/Year

Correction Factor

Glucose Range

Population

Clinical Use

Katz (1973)

1.6 mEq/L Na decrease per 100 mg/dL glucose increase above 100 mg/dL

Any hyperglycemia (derived from studies with glucose <600 mg/dL)

General medical inpatients

Most widely used; simple, single factor. Suitable for most clinical settings.

Hillier (1999)

Varies: 2.4 mEq/L per 100 mg/dL for glucose >400 mg/dL; 2.0 mEq/L per 100 mg/dL for glucose 200-400 mg/dL

Up to 1,500 mg/dL

65 hyperglycemic patients (DKA, HHS, other)

More accurate at very high glucose (>400 mg/dL). Preferred in HHS and severe DKA.

Moran & Jamison (1978)

1.6 mEq/L (same as Katz)

Limited range

Not widely used

Historical; same as Katz.

Turchin (2005)

1.6 mEq/L (validated in large cohort)

Mean glucose 415 mg/dL (range 200-1,200)

12,000+ hospitalized patients (retrospective)

Confirmed Katz factor in large dataset; no need for adjustment based on renal function?

Pediatric DKA (ISPAD)

1.6 mEq/L (Katz) OR 1.6/3? Actually ISPAD uses 1.6

Pediatric DKA

Children

Same as Katz; monitor trend (rise of 3 mEq/L in 4 hours predicts cerebral edema)

UK Joint British Diabetes Societies (JBDS)

1.5-2.0 mEq/L (range), often uses 1.6

DKA and HHS

Adult inpatients

Recommends Katz; also recommends monitoring measured sodium rise (should increase as glucose falls)

Corrected Sodium Range

Interpretation

Fluid Management Implication

Key Action

<135 mEq/L

True hyponatremia (total body water excess relative to sodium, despite hyperglycemia)

Patient may be volume overloaded (heart failure, cirrhosis, SIADH) or have severe true sodium deficit. Use 0.9% NaCl (normal saline) or even hypertonic saline (3%) if severe (<120 mEq/L with neurological symptoms). Avoid 0.45% NaCl (hypotonic).

Check volume status, consider underlying cause of true hyponatremia (SIADH, heart failure, adrenal insufficiency). Monitor closely for overcorrection.

135-145 mEq/L

Normonatremia (true sodium normal; measured low due to dilution only)

Patient is eunatremic. Use 0.9% NaCl initially (resuscitation) then transition to 0.45% NaCl once glucose <250 mg/dL and corrected sodium stable.

Standard DKA/HHS protocol. Monitor measured sodium rise as glucose falls (should increase).

>145 mEq/L

True hypernatremia (free water deficit, severe volume depletion)

Patient is water-depleted. Use 0.45% NaCl (hypotonic) initially to correct free water deficit. Avoid 0.9% NaCl (may worsen hypernatremia by adding sodium without enough water).

Calculate free water deficit (0.6 × weight in kg × [serum Na/140 - 1]). Replace deficit over 48 hours. Monitor corrected sodium trend.

>160 mEq/L (HHS)

Severe hypernatremia, massive free water deficit

Use 0.45% NaCl (hypotonic) or 0.9% NaCl if hypotensive, but transition to hypotonic as soon as hemodynamically stable. Consider enteral water (NG) if possible.

Replace free water deficit slowly (8-12 mEq/L per day maximum correction). Risk of cerebral edema if overcorrected too rapidly.

Time Period

Expected Change in Measured Na

Clinical Significance

Action if Change Exceeds Range

First 4 hours of insulin/fluids

Increase of 1-2 mEq/L (mild rise)

Normal response; water shifts back into cells as glucose is metabolized/in excreted.

If no rise or decrease, suspect: (1) Too much free water (hypotonic fluids), (2) Continuing water loss (osmotic diuresis from glucose), (3) True hyponatremia (adrenal insufficiency, SIADH). Adjust fluid type (reduce free water).

Over 24 hours

Total increase of 4-8 mEq/L

Sodium should trend toward corrected sodium value as glucose normalizes.

If measured Na rises too fast (>12 mEq/L in 24 hours), risk of cerebral edema (especially children). Slow fluid rate, consider adding dextrose (D5 0.45% NaCl) to prevent too-rapid glucose fall.

In children (DKA)

Increase of ≤3 mEq/L in first 4 hours (ISPAD guideline)

Rise >3 mEq/L in 4 hours associated with increased cerebral edema risk.

If rise >3 mEq/L, slow IV fluid rate, consider adding dextrose, notify PICU. Perform neurological exam q1h.

In HHS (very high glucose)

May rise 10-20 mEq/L over 24 hours (free water deficit correction)

Expected, as fluid deficit is replaced (using 0.45% NaCl or 0.9% NaCl with enteral water).

Monitor neurological status (confusion, lethargy, coma). Avoid too-rapid correction of hyperosmolality (target decrease of 3-8 mOsm/kg/hour).

Corrected Sodium

Initial Fluid (First 1-2 hours)

Subsequent Fluid (After Glucose <250 mg/dL)

Special Considerations

<135 mEq/L (true hyponatremia)

0.9% NaCl (normal saline) bolus 10-20 mL/kg if hypotensive, then 250-500 mL/hr (adults). Avoid hypotonic fluids.

0.9% NaCl with potassium. Consider adding D5 after glucose <250 to prevent too-rapid glucose fall. Evaluate for adrenal insufficiency, SIADH, heart failure.

If severe (<120 mEq/L with neurological symptoms), consider 3% hypertonic saline (slow, monitored). Check cortisol urgently.

135-145 mEq/L (normonatremia)

0.9% NaCl (standard DKA/HHS protocol). Bolus 10-20 mL/kg if hypotensive (HHS often needs more).

Switch to 0.45% NaCl with potassium once glucose <250 mg/dL (adults) or <300 mg/dL (children) to provide free water and prevent too-rapid glucose fall.

Monitor measured Na rise; if increases >3 mEq/L in 4 hours (pediatric), slow rate, add dextrose earlier.

>145 mEq/L (true hypernatremia, water depletion)

0.9% NaCl if hypotensive (briefly). If euvolemic or hypervolemic, use 0.45% NaCl (hypotonic).

0.45% NaCl with potassium. Add D5 when glucose <250 to prevent hypoglycemia and provide free water. Consider enteral water (via NG) if alert and able to swallow.

Calculate free water deficit: Total body water (0.6× weight in kg) × (serum Na/140 - 1). Replace deficit over 48 hours (1/2 in first 24 hours). Avoid 0.9% NaCl (worsens hypernatremia).

Year

Contributor(s)

Institution

Contribution

1973

Katz MA

University of Texas Medical Branch, Galveston, TX

Derivation of correction factor (1.6 mEq/L per 100 mg/dL glucose). NEJM letter.

1978

Moran SM, Jamison RL

Stanford University

Validation of Katz factor in small cohort.

1999

Hillier TA, Abbott RD, Barrett EJ

University of Virginia, Charlottesville, VA

Refinement: non-linear correction (2.0 for glucose 200-400, 2.4 for >400). Am J Med paper.

2005

Turchin A, Matheny ME, Shubina M, et al.

Brigham and Women's Hospital, Boston, MA

Large validation (12,000+ patients) comparing Katz and Hillier; both have utility depending on glucose level.

2006

American Diabetes Association (ADA) Guidelines

ADA

First inclusion of corrected sodium in DKA/HHS management algorithms.

2018

ISPAD Guidelines (Wolfsdorf JI, et al.)

International Society for Pediatric and Adolescent Diabetes

Formal recommendation for corrected sodium monitoring in pediatric DKA with specific thresholds for cerebral edema prevention.

2023

JBDS DKA Guidelines (UK)

Joint British Diabetes Societies

Recommend corrected sodium using Katz factor (1.6) for DKA; emphasize trend over single value.

Corrected Sodium (Hyperglycaemia)

When to Use

What is Corrected Sodium (Hyperglycemia Correction)?

Primary Clinical Indications

Contraindications / Limitations

Comparison of Correction Factors (Katz vs Hillier vs Others)

How it Works

Standard Corrected Sodium Formula (Katz 1973)

Alternative Formula (Hillier 1999, Glucose >400 mg/dL)

Interpretation of Corrected Sodium in Hyperglycemia

Expected Rise in Measured Sodium as Glucose Falls (DKA/HHS)

Clinical Pearls

Critical Pearl #1: Use Corrected Sodium to Guide Fluid Selection, Not Measured Sodium

Critical Pearl #2: In DKA, Measured Na Should Rise as Glucose Falls

Critical Pearl #3: For Glucose >400 mg/dL, Consider Hillier Factor (2.4) for Accuracy

Critical Pearl #4: Corrected Sodium Helps Predict Risk of Cerebral Edema in Pediatric DKA

Common Pitfalls in Corrected Sodium Use

Fluid Management Algorithm Based on Corrected Sodium

Next Steps

Step-by-Step Clinical Action Based on Corrected Sodium

Calculating Free Water Deficit in HHS with Hypernatremia

Sample Clinical Documentation for Corrected Sodium Cases

The Evidence

Primary Source: Katz (1973)

Hyperglycemia-induced hyponatremia: calculation of expected serum sodium concentration

Refinement: Hillier (1999)

Hyponatremia and hypercalcemia in acute hyperglycemia: a new look at an old problem

Large Validation Study: Turchin (2005)

Hyperglycemia and hyponatremia in hospitalized patients: should the correction factor be 1.6 or 2.4?

Pediatric DKA Guidelines (ISPAD, AAP)

ISPAD Clinical Practice Consensus Guidelines 2018: Diabetic ketoacidosis and hyperglycemic hyperosmolar state

Origins & History

Katz and the Birth of Corrected Sodium

Key Contributors and Timeline

Future Directions

In Recent Clinical News

Corrected Sodium (Hyperglycaemia)

When to Use

What is Corrected Sodium (Hyperglycemia Correction)?

Primary Clinical Indications

Contraindications / Limitations

Comparison of Correction Factors (Katz vs Hillier vs Others)

How it Works

Standard Corrected Sodium Formula (Katz 1973)

Alternative Formula (Hillier 1999, Glucose >400 mg/dL)

Interpretation of Corrected Sodium in Hyperglycemia

Expected Rise in Measured Sodium as Glucose Falls (DKA/HHS)

Clinical Pearls

Critical Pearl #1: Use Corrected Sodium to Guide Fluid Selection, Not Measured Sodium

Critical Pearl #2: In DKA, Measured Na Should Rise as Glucose Falls

Critical Pearl #3: For Glucose >400 mg/dL, Consider Hillier Factor (2.4) for Accuracy

Critical Pearl #4: Corrected Sodium Helps Predict Risk of Cerebral Edema in Pediatric DKA

Common Pitfalls in Corrected Sodium Use

Fluid Management Algorithm Based on Corrected Sodium

Next Steps

Step-by-Step Clinical Action Based on Corrected Sodium

Calculating Free Water Deficit in HHS with Hypernatremia

Sample Clinical Documentation for Corrected Sodium Cases

The Evidence

Primary Source: Katz (1973)

Hyperglycemia-induced hyponatremia: calculation of expected serum sodium concentration

Refinement: Hillier (1999)

Hyponatremia and hypercalcemia in acute hyperglycemia: a new look at an old problem

Large Validation Study: Turchin (2005)

Hyperglycemia and hyponatremia in hospitalized patients: should the correction factor be 1.6 or 2.4?

Pediatric DKA Guidelines (ISPAD, AAP)

ISPAD Clinical Practice Consensus Guidelines 2018: Diabetic ketoacidosis and hyperglycemic hyperosmolar state

Origins & History

Katz and the Birth of Corrected Sodium

Key Contributors and Timeline

Future Directions

In Recent Clinical News