Lab

Serum Sodium

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Serum Sodium, Serum Na, Corrected Serum Sodium for Glucose, Corrected Serum Sodium for Hyperglycemia

  • Physiology
  • Sodium homeostasis
  • Interpretation
  • General
  1. Normal: 135-145 mEq/L
  2. Abnormal
    1. Hypernatremia
      1. Serum Sodium over 145
    2. Hyponatremia
      1. Serum Sodium under 135
  • Interpretation
  • Corrected Serum Sodium for Glucose
  1. Glucose draws water into the intravascular space via osmotic pressure, and dilutes Serum Sodium
    1. Measured Serum Sodium in hyperglycermia is a true Hyponatremia
    2. However the Serum Sodium corrects with normalization of Glucose
  2. Adjust measured Serum Sodium (sNa) upwards by 1.6 meq/L per 100 mg/dl increase in plasma Glucose
    1. Corrected Serum Sodium = sNa + 0.016 * (Serum Glucose - 100)
    2. Katz (1973) N Engl J Med 289(16): 843-4 [PubMed]
  3. Alternative equation suggests correction should be 2.4 meq/L per 100 mg/dl increase in plasma Glucose
    1. Although Hillier equation is thought more accurate, Katz equation is used most commonly
    2. Hillier (1999) Am J Med 106(4): 399-403 [PubMed]
  • Resources