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Bicarbonate Concentration in Blood (Serum or Plasma)

Published: August 9, 2026Updated: August 17, 2026

This test measures the amount of bicarbonate ions in your blood, which helps balance your body’s acidity and alkalinity. It’s often checked when evaluating conditions affecting acid-base balance.

Quick summary

["Bicarbonate helps regulate your body’s pH and is key to detecting acid-base imbalances."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 17, 2026Editorial policy

Key facts at a glance

LOINC
1960-4
Short code
HCO3 BldA-sCnc
Synonyms
HCO3 BldA-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
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 This Test Is Done

Your doctor may order this test if you have symptoms like fatigue, confusion, shortness of breath, or muscle weakness. It’s also used to monitor conditions like kidney disease, metabolic disorders, or respiratory issues that affect acid-base balance.

What to Expect Before the Test

No special preparation is needed. You may have a small needle inserted into a vein (venipuncture) to draw blood, or a finger prick for capillary blood. The test is quick and usually done in a lab setting.

What the Results Mean

Results help determine if your bicarbonate levels are too high or too low, which can indicate problems like metabolic acidosis or alkalosis. Your doctor will compare these results with your symptoms and other tests.

Common Conditions Affecting Bicarbonate Levels

Low bicarbonate (metabolic acidosis) may occur due to kidney problems, diarrhea, or excessive vomiting. High bicarbonate (metabolic alkalosis) can result from conditions like severe vomiting, overuse of antacids, or dehydration.

Reference range

NCBI: HCO3- 22-28 mmol/LN/A

Specimen: whole-blood

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.

◆Associated findings1

Short name

Bicarbonate Level

Frequently asked questions

What causes bicarbonate levels to change?
Several factors can affect bicarbonate levels, including kidney function (since they regulate bicarbonate), gastrointestinal conditions (like vomiting or diarrhea), respiratory issues (like chronic obstructive pulmonary disease), and certain medications (like antacids). Lifestyle factors, such as diet or hydration status, may also play a role.
How long does it take to get results?
Test results are typically available within 1 to 3 business days, depending on your lab’s processing time. Your doctor will contact you once they have the results, especially if they are outside of expected ranges.
Can I eat or drink before this test?
No special diet or fasting is required for this test. However, if you’re scheduled for a blood draw, avoid caffeine or heavy meals 2–3 hours before the test to ensure accurate results.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

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.

Medical Disclaimer

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