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Bicarbonate concentration in 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 acidity (pH). It plays a vital role in maintaining balance and supporting normal bodily functions.

Quick summary

["Bicarbonate helps balance blood acidity and supports healthy metabolism."]

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

Key facts at a glance

LOINC
16462-4
Short code
HCO3 Amn-sCnc
Synonyms
HCO3 Amn-sCnc
Category
chemistry
Sample
fluid
Container
Sterile tube
Units
N/A
Ref low
22
Ref high
28
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Specimen volume
2-5 mL
Stability
Room temperature: 2h, Refrigerated: 24h
Hemolysis max
300
TAT
4–24 hours
Order
routine

Why Is This Test Done?

Your healthcare provider may order this test to check for conditions affecting acid-base balance, such as metabolic acidosis or alkalosis. It’s often used alongside other blood tests like blood pH and electrolytes to diagnose or monitor diseases like kidney problems, diabetes, or respiratory disorders.

What to Expect Before the Test

No special preparation is usually needed. You may have a small needle inserted into a vein (venipuncture) in your arm to draw blood. If you’re on a blood thinner, let your provider know beforehand.

What Happens During the Test?

A healthcare professional will clean the arm with an antiseptic, insert a needle into a vein, and collect a blood sample into a tube. The process typically takes a few minutes. You may feel a slight pinch or discomfort, but it’s usually over quickly.

What Are the Possible Results?

Results are interpreted in relation to your overall health and other blood tests. Abnormally low bicarbonate levels may suggest metabolic acidosis, while abnormally high levels may indicate metabolic alkalosis. Your provider will discuss these findings with you.

Reference range

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

Specimen: fluid

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.

Clinical Significance

Short name

Bicarbonate (HCO₃⁻)

Frequently asked questions

What Does a Low Bicarbonate Level Mean?
Low bicarbonate levels can occur due to conditions like kidney disease, severe vomiting, or diabetic ketoacidosis. It may also happen if you’re retaining too much acid in your body. Your provider will work with you to identify and address the underlying cause.
What Does a High Bicarbonate Level Mean?
High bicarbonate levels can result from conditions like severe dehydration, overuse of antacids, or certain kidney disorders. It may also occur if you’re losing too much acid in your body, such as through excessive vomiting or diarrhea. Your provider will investigate further to determine the reason.
How Often Should I Get This Test?
Your provider will decide how often you need this test based on your health condition and symptoms. Regular monitoring may be necessary if you have chronic kidney disease, diabetes, or other conditions affecting acid-base balance.
  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