Enter ABG values

pH is calculated using: pH = 6.1 + log10( HCO₃⁻ / (0.03 × PaCO₂) )

Result
Calculated pH: —
Letters:
pH: CO₂: HCO₃⁻:
Pattern:
Enter PaCO₂ and HCO₃⁻ to see letters, pattern, and diagnosis.
Rules for ABC ABG

A = Acid (pH < 7.35, CO₂ > 45, HCO₃⁻ < 22)
B = Base (pH > 7.45, CO₂ < 35, HCO₃⁻ > 26)
N = Normal (within range)

Interpretation:
A + A + N = Acidosis → who caused it? If CO₂ is A → Respiratory; if HCO₃⁻ is A → Metabolic
B + B + N = Alkalosis → who caused it? CO₂ (B) = Respiratory; HCO₃⁻ (B) = Metabolic
A + B + N (or B + A + N) with pH ≈ normal → Compensated (use pH tilt around 7.40 for direction)
N + N + N = Normal
If pH is A (or B) and both CO₂ & HCO₃⁻ are also A (or B) → Mixed disorder

Example: pH 7.20, CO₂ 55, HCO₃⁻ 24 → pH=A, CO₂=A, HCO₃⁻=N → A + A + N = Acidosis. Cause: CO₂ is A → Respiratory acidosis.