Bicarbonate

Background

• Primary buffer in the blood; measured as total CO2 on chemistry panels
• Reflects acid-base status in conjunction with pCO2

Normal Values

• Normal: 22-28 mEq/L

Interpretation

• Low bicarbonate indicates metabolic acidosis; evaluate with anion gap
  • Anion gap acidosis: DKA, lactic acidosis, toxic ingestions (MUDPILES), renal failure
  • Non-anion gap acidosis: diarrhea, RTA, normal saline infusion
• Elevated bicarbonate indicates metabolic alkalosis (vomiting, diuretics, contraction alkalosis) or chronic respiratory acidosis compensation
• Venous CO2 on BMP closely approximates arterial bicarbonate (typically within 1-2 mEq/L)

See Also

• BMP
• Anion gap
• ABG interpretation
• Metabolic acidosis
• Sodium bicarbonate