ICU and Critical Care · Anaesthesiology

Base Excess (Siggaard-Andersen) calculator

Enter the published formula inputs below to calculate and interpret this score.

Clinical inputs

Allowed range: 6.8–7.8 pH

Bicarbonate (mmol/L)

mmol/L

Allowed range: 5–45 mmol/L

Result

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Professional use only

For qualified clinicians. Independently verify inputs, calculations, source guidance, and applicability before any clinical action. This calculator does not replace clinical judgment.

Source: Standard (extracellular fluid) base excess by the Van Slyke equation (Siggaard-Andersen O. The Van Slyke equation. Scand J Clin Lab Invest Suppl. 1977;146:15-20), in the representative form used by LOINC 97546-6: SBE (mmol/L) = 0.9287 × [HCO3⁻ − 24.4 + 14.83 × (pH − 7.4)]. Normal range −2 to +2 mmol/L (Langer T, Brusatori S, Gattinoni L. Understanding base excess (BE): merits and pitfalls. Intensive Care Med. 2022;48:1080-1083. DOI: 10.1007/s00134-022-06748-4); negative values indicate a non-respiratory (metabolic) acidosis component and positive values a metabolic alkalosis component. (2022)

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Clinical inputs

pHAccepted range: 6.8 to 7.8
Bicarbonate (mmol/L)Accepted range: 5 to 45

Primary source

Standard (extracellular fluid) base excess by the Van Slyke equation (Siggaard-Andersen O. The Van Slyke equation. Scand J Clin Lab Invest Suppl. 1977;146:15-20), in the representative form used by LOINC 97546-6: SBE (mmol/L) = 0.9287 × [HCO3⁻ − 24.4 + 14.83 × (pH − 7.4)]. Normal range −2 to +2 mmol/L (Langer T, Brusatori S, Gattinoni L. Understanding base excess (BE): merits and pitfalls. Intensive Care Med. 2022;48:1080-1083. DOI: 10.1007/s00134-022-06748-4); negative values indicate a non-respiratory (metabolic) acidosis component and positive values a metabolic alkalosis component. (2022)

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