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Bicarbonate (blood gas)

Blood gases · also printed as HCO3 (gas), cHCO3, HCO3- (blood gas), Bicarb (ABG), Bicarbonate (ABG)

Typical UK adult range22 to 28 mmol/L

Ranges vary between laboratories; the range printed on the report takes precedence.

What this test measures

The bicarbonate reported on a blood gas is calculated from the pH and pCO2. It reflects the kidney's contribution to acid balance.

Why doctors request it

Part of every blood gas, read with pH and pCO2 to separate breathing from metabolic causes.

What commonly pushes it up

Long-term lung disease with carbon dioxide retention, as compensation
Vomiting
Some water tablets as a class

What commonly pushes it down

Kidney failure
Diabetic ketoacidosis
Severe infection
Diarrhoea

Everyday reasons for a value outside the range

It is calculated, so it differs slightly from the measured bicarbonate on a chemistry panel

About the sample

Read with pH and pCO2.

Written by a UK consultant physician. Typical UK adult reference ranges; your laboratory's own printed range takes precedence.

Got a report with Bicarbonate (blood gas) on it?

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This is an educational summary of results you uploaded. It is not medical advice, a diagnosis or a treatment plan, and it does not replace the doctor who requested the test. If you are worried, or a result is marked outside range, discuss it with your doctor. Written and reviewed by a UK consultant physician. Reference ranges vary between laboratories.