Bicarbonate (HCO₃⁻) concentration in plasma
This test measures the amount of bicarbonate, a key chemical in your blood that helps regulate acidity (pH). It’s part of your body’s effort to balance acid-base levels.
["Bicarbonate helps maintain healthy blood pH and supports normal bodily functions, including metabolism and nerve function."]
Key facts at a glance
- LOINC
- 1962-0
- Short code
- Deprecated HCO3 Plas-sCnc
- Synonyms
- Deprecated HCO3 Plas-sCnc
- Category
- chemistry
- Sample
- plasma
- Container
- Lavender-top (EDTA) or Green-top (Heparin)
- Units
- N/A
- Ref low
- 22
- Ref high
- 28
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Specimen volume
- 5 mL
- Stability
- Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 4–24 hours
- Order
- routine
Why Is This Test Done?
Your doctor may order this test to check for conditions that affect how well your body balances acid and base, such as metabolic acidosis or alkalosis. It can also help diagnose or monitor conditions like kidney disease, diabetes, or respiratory disorders.
What Does a Low or High Level Mean?
Low bicarbonate levels may indicate too much acid in your blood (acidosis), which can happen due to kidney problems, severe vomiting, or certain medications. High levels might suggest too much base (alkalosis), often seen in conditions like overuse of antacids or severe dehydration.
Sample Collection and Preparation
A blood sample is taken from a vein in your arm. The sample is collected in a special tube that separates plasma from blood cells. This plasma is then analyzed in a lab to measure bicarbonate concentration.
What to Expect Before the Test
No special preparation is usually needed, but you may be asked to fast for a few hours if your doctor specifies it. Avoiding certain medications or foods for a day before the test can help ensure accurate results.
Reference range
NCBI: HCO3- 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.
Bicarbonate levels are closely tied to overall acid-base balance in your body. Abnormal levels can signal underlying health issues, such as metabolic disorders, kidney dysfunction, or fluid imbalances. Your doctor may also use bicarbonate levels alongside other tests, like blood pH or carbon dioxide levels, to diagnose conditions like diabetic ketoacidosis or respiratory failure.
Short name
Plasma bicarbonate level
Frequently asked questions
What causes bicarbonate levels to change?
How long does it take to get results?
Can lifestyle changes affect bicarbonate levels?
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 17, 2026. · Read our editorial policy