Arterial Blood Carbon Dioxide Partial Pressure (Calculated)
This test measures the amount of carbon dioxide gas dissolved in your blood from an artery (arterial blood), using a calculated value based on blood chemistry measurements. It helps assess how well your body is balancing oxygen and carbon dioxide levels.
["This test helps doctors diagnose and monitor conditions affecting gas exchange in your lungs and blood circulation."]
Key facts at a glance
- LOINC
- 34728-6
- Short code
- CO2 Bld Calc-sCnc
- Synonyms
- CO2 Bld Calc-sCnc
- Category
- chemistry
- Sample
- whole-blood
- Container
- Lavender-top (EDTA)
- Units
- N/A
- Ref low
- 22
- Ref high
- 28
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- calculated
- CPT
- 82374
- Specimen volume
- 3 mL
- Stability
- Room temperature: 4h, Refrigerated: 24h
- Hemolysis max
- 0
- Lipemia max
- 0
- Icterus max
- 0
- TAT
- 4–24 hours
- Order
- routine
Why Is This Test Done?
Your healthcare provider may order this test if you have symptoms like shortness of breath, chest pain, or fatigue that could indicate problems with how your lungs or heart move oxygen and carbon dioxide. It’s also used in critical care settings, such as the ICU, to monitor patients with severe respiratory or circulatory issues.
What Does the Result Mean?
The result is expressed in millimeters of mercury (mmHg) and is calculated from other blood measurements. Abnormal values may suggest conditions like respiratory failure, metabolic issues, or fluid imbalances.
How Is the Test Performed?
A small sample of blood is taken from an artery in your arm or wrist. The blood is analyzed in a lab to determine the carbon dioxide levels, and the result is calculated based on standard formulas.
What Are Common Causes of Abnormal Results?
Low arterial CO₂ levels (hypocapnia) may occur due to hyperventilation, lung diseases, or overbreathing. High levels (hypercapnia) can result from conditions like chronic obstructive pulmonary disease (COPD), obesity hypoventilation syndrome, or kidney problems.
Reference range
Adult: 22-28 mmol/LN/A
No special preparation usually required. Stay well hydrated. Inform your healthcare provider of all medications and supplements you are taking.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
This test plays a key role in diagnosing and managing respiratory and metabolic disorders. It helps doctors adjust treatments, such as oxygen therapy or mechanical ventilation, to improve oxygenation and carbon dioxide removal in the body.
Short name
CO₂ (Arterial) Calculation
Frequently asked questions
What does an abnormal arterial CO₂ level indicate?
How often should I expect this test?
Can I prepare for this test?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.
This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy