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Serum Sodium
Aka: Serum Sodium, Serum Na, Corrected Serum Sodium for Glucose, Corrected Serum Sodium for Hyperglycemia
- See Also
- Sodium and Water Homeostasis
- Hyponatremia
- Hypernatremia
- Total Body Sodium Deficit (Includes Total Body Water and Free Water Deficit Calculations)
- Serum Osmolality
- Osmolal Gap
- Urine Sodium
- Fractional Excretion of Sodium (FENa)
- Physiology: Sodium homeostasis
- See Sodium and Water Homeostasis
- Interpretation: General
- Normal: 135-145 mEq/L
- Abnormal
- Hypernatremia
- Serum Sodium over 145
- Hyponatremia
- Serum Sodium under 135
- Interpretation: Corrected Serum Sodium for Glucose
- Glucose draws water into the intravascular space via osmotic pressure, and dilutes Serum Sodium
- Measured Serum Sodium in hyperglycermia is a true Hyponatremia
- However the Serum Sodium corrects with normalization of Glucose
- Katz Formula
- Adjust measured Serum Sodium (sNa) upwards by 1.6 meq/L per 100 mg/dl increase in plasma Glucose
- Corrected Serum Sodium = sNa + 0.016 * (Serum Glucose - 100)
- Katz (1973) N Engl J Med 289(16): 843-4 [PubMed]
- Hillier Formula
- Alternative equation suggests correction should be 2.4 meq/L per 100 mg/dl increase in plasma Glucose
- Corrected Serum Sodium = sNa + 0.024 * (Serum Glucose - 100)
- Although Hillier equation is thought more accurate, Katz equation is used most commonly
- Hillier (1999) Am J Med 106(4): 399-403 [PubMed]
- Resources
- MDCalc Corrected Serum Sodium
- http://www.mdcalc.com/sodium-correction-for-hyperglycemia/
- References
- Braun (2015) Am Fam Physician 91(5): 299-307 [PubMed]