CO2

Abbreviation with 2 meanings

CO2
Stands forCarbon dioxide
Meanings2
CategoriesScience & Engineering, Medical

CO2 has two meanings. It stands for Carbon dioxide (chemistry) or Total carbon dioxide (serum bicarbonate) (laboratory test).

Meanings of CO2 at a glance

#CO2 stands forContext
1Carbon dioxideScience & Engineering › Chemistry
2Total carbon dioxide (serum bicarbonate)Medical › Laboratory Test

1. Carbon dioxide

Science & Engineering · Chemistry Abbreviations

Colorless gas produced when carbon-containing fuels burn and when organisms respire, and absorbed by plants during photosynthesis. Carbon dioxide is the main greenhouse gas driving climate change; its atmospheric concentration has risen from about 280 parts per million before industrialization to more than 420 ppm.

Example: The meeting room's CO2 monitor read 1,400 ppm, so the ventilation was turned up.

Formally written with a subscript 2. Solid CO2 is dry ice, which turns straight to gas at -78.5 °C. Carbonated drinks, fire extinguishers, greenhouse enrichment and supercritical-CO2 decaffeination all rely on it. Joseph Black identified it as "fixed air" in the 1750s. Climate reports use CO2e to express the combined effect of several greenhouse gases.

2. Total carbon dioxide (serum bicarbonate)

Medical · Laboratory Test Abbreviations

On a BMP or CMP, the line labeled CO2 measures the total carbon dioxide content of serum, roughly 95 percent of which is bicarbonate, so it effectively reports bicarbonate with a normal range around 23 to 29 mmol/L. It is a metabolic acid-base marker, not a measure of breathing.

Example: Patient portal question: my CO2 was 19, low on the report; is that from my asthma?

Patients often read a low CO2 as a lung problem, but the respiratory value is PaCO2 on an arterial blood gas, a separate test. Underfilled tubes or samples left uncapped lose carbon dioxide to the air and give falsely low results. Labs variously label it CO2, TCO2, total CO2 or bicarbonate.

More chemistry abbreviations

  • CAS – Chemical Abstracts Service
  • CFC – Chlorofluorocarbon
  • CH4 – Methane
  • CO – Carbon monoxide
  • conc. – Concentrated
  • DCM – Dichloromethane
  • DDT – Dichlorodiphenyltrichloroethane
  • DFT – Density functional theory

See all 106 chemistry abbreviations →

More laboratory test abbreviations

  • CK-MB – Creatine kinase-MB isoenzyme
  • Cl – Chloride
  • CLIA – Clinical Laboratory Improvement Amendments
  • CMP – Comprehensive metabolic panel
  • CPK – Creatine phosphokinase
  • Cr – Creatinine
  • CrCl – Creatinine clearance
  • CRP – C-reactive protein

See all 135 laboratory test abbreviations →

Edited by the AbbreviationList.com team. Spotted an error or a missing meaning? Contact us.

This entry is for general education and is not medical advice. Abbreviation use varies between institutions; always confirm in context.