CO₂ (Bicarbonate, serum)
BMP / ElectrolytesNormal range
23–30 mEq/L
SI: 23–30 mmol/L
Critical low: < 15 mEq/L · Critical high: > 40 mEq/L
☎ When to call
CO₂ < 18 with an unwell patient (possible DKA/sepsis) — escalate with the full picture: vitals, glucose, mentation.
What you do
- A low CO₂ on a BMP is a metabolic acidosis clue — look at the patient: Kussmaul respirations? Check glucose, lactate, renal function
- Pair with ABG when the picture is unclear
Causes of HIGH co₂
Causes of LOW co₂
Source: Pagana, Mosby's Manual of Diagnostic and Laboratory Tests, 7th ed.Reference only — verify against your facility's policy.
