Base excess (also known as base deficit) is a calculated parameter included with blood gas results.
Base excess refers to the amount of base that would need to be added or taken away in order to normalise the pH, assuming that the pCO2 of the sample was normal. It is an indirect marker of the metabolic component of the acid-base disorder.
BE, base deficit
Patient Specimen - 500uL whole blood in heparinised blood gas syringe
Paediatric Specimen 200 uL whole blood in a 1 mL syringe
Capped syringe sent to lab on ice, within 15 mins.
Aliquot Instructions - 200 uL whole blood in a 1 mL syringe.
Aliquot Transport to CHL - On ice, sample must be kept anaerobic
A normal base excess is between -3mmol/L and +3mmol/L
In a metabolic acidosis, the base excess will be negative. The lower the base excess, the more severe the metabolic acidosis.
Conversely, a positive base excess is seen in a metabolic alkalosis (i.e. there is an excess of base present in the specimen). Again, the magnitude of the elevation will give an indication as to the severity of the alkalosis.
Base excess will not be influenced by the presence or absence of a coexisting respiratory acid-base disturbance.
-3 – +3 mmol/L
Calculated from blood gas parameters
Treat as urgent
"*" indicates required fields