Biomarker education

CO2 (bicarbonate): What It Measures & Why People Track It

Also called: Carbon dioxide, Bicarbonate, HCO3, CO2 total, CO2, Total CO2

This test estimates bicarbonate, part of the body's acid-base balance, and is part of metabolic panels.

General biomarker education — not personalized medical advice. Learn more

Result on your report

Illustrative

CO2 (bicarbonate)

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Range: Low – High

LowReference intervalHigh

What it generally measures

Labs measure total carbon dioxide in blood, which is mostly bicarbonate — a marker used alongside others to look at the body's acid-base status.

Common units on reports: mmol/L

CO2 is generally reviewed as one part of the full electrolyte panel rather than by itself.

Changes over time do not by themselves establish a diagnosis. Learn more

Questions to bring

Illustrative

Ask how CO2 fits with the other electrolytes on your panel.

Ask whether breathing, medications, or other factors your clinician has discussed could affect this value.

Organize your own lab history

Part of Kind Panel education · Lab results guide

Reference range

CO2 (bicarbonate) reference range

What the range on your report means for this marker.

Panel guide

Related panel guide

Understand the broader panel this marker appears on.

Related biomarker

Sodium

Sodium is an electrolyte that helps regulate fluid balance and is part of most metabolic panels.