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Bicarbonate concentration in blood (serum/plasma)

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

This test measures the amount of bicarbonate, a key chemical in your blood that helps regulate your body’s acid-base balance.

Quick summary

["Bicarbonate helps balance acidity in your blood, which is crucial for normal body function and health."]

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

Key facts at a glance

LOINC
14151-5
Short code
HCO3 BldCo-sCnc
Synonyms
HCO3 BldCo-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

What bicarbonate measures

Bicarbonate is a critical buffer in your blood, helping to neutralize acids and maintain a stable pH. It plays a key role in preventing blood from becoming too acidic or too alkaline, which can affect how your body functions, including breathing, muscle function, and kidney function.

Why it matters in your health

Abnormal bicarbonate levels can signal underlying health issues, such as metabolic disorders, kidney problems, or conditions affecting how your body processes acids and bases.

How the test works

This test involves drawing blood from a vein in your arm. The blood sample is then analyzed to determine the concentration of bicarbonate ions. The method used may include chemical reactions or specialized instruments to measure the level accurately.

When you might need this test

Your doctor may order this test if you have symptoms like shortness of breath, fatigue, muscle weakness, or if they suspect conditions like metabolic acidosis or alkalosis, kidney disease, or other acid-base imbalances.

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 (HCO₃⁻) level

Frequently asked questions

What does a low bicarbonate level mean?
A low bicarbonate level may indicate an imbalance in your body’s acid-base chemistry, which can be caused by conditions like kidney problems, severe dehydration, or metabolic disorders. Your doctor will discuss further tests or treatments based on your symptoms and overall health.
What does a high bicarbonate level mean?
High bicarbonate levels can suggest an overcompensation for acid in your body, often seen in conditions like severe vomiting, excessive use of antacids, or certain kidney disorders. This may also be part of a broader evaluation for metabolic alkalosis.
Does diet affect bicarbonate levels?
Dietary factors like high salt intake or certain foods may indirectly influence acid-base balance, but bicarbonate levels are primarily regulated by your kidneys and lungs. Your doctor will consider your overall health and medical history when interpreting 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