This implementation uses arterial pH, PaCO₂, bicarbonate, sodium, chloride and albumin.

Anion gap = Na⁺ − Cl⁻ − HCO₃⁻
Albumin-corrected anion gap = anion gap + 0.25 × [40 − albumin (g/L)]
Delta ratio = [corrected anion gap − 12] ÷ [24 − HCO₃⁻]

Primary disorder	Displayed expected compensation
Metabolic acidosis	PaCO₂ = 1.5 × HCO₃⁻ + 8 mmHg
Metabolic alkalosis	PaCO₂ = 0.7 × HCO₃⁻ + 20 mmHg
Acute respiratory acidosis	HCO₃⁻ = 24 + 0.1 × (PaCO₂ − 40)
Chronic respiratory acidosis	HCO₃⁻ = 24 + 0.35 × (PaCO₂ − 40)
Acute respiratory alkalosis	HCO₃⁻ = 24 + 0.2 × (PaCO₂ − 40)
Chronic respiratory alkalosis	HCO₃⁻ = 24 + 0.5 × (PaCO₂ − 40)

The implementation adds 0.0001 to the delta-ratio denominator to prevent division by zero. Do not interpret the delta ratio when bicarbonate has not fallen below 24 mmol/L or the corrected anion gap is not elevated.

Arterial blood gas (ABG) analyser