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Bicarbonate (HCO₃⁻) concentration in serum/plasma

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

This test measures the amount of bicarbonate ions in your blood, which helps regulate your body’s acid-base balance. Bicarbonate is a key part of how your kidneys and lungs maintain healthy pH levels in your bloodstream.

Quick summary

["Bicarbonate levels help diagnose and monitor conditions affecting acid-base balance."]

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

Key facts at a glance

LOINC
19231-0
Short code
HCO3 std BldC-sCnc
Synonyms
HCO3 std BldC-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 Is This Test Done?

Your healthcare provider may order this test if you have symptoms like unusual fatigue, shortness of breath, muscle weakness, or signs of metabolic issues. It’s also used to check for conditions like kidney disease, diabetes, or respiratory problems that affect how your body handles acids and bases.

What to Expect Before the Test

No special preparation is needed. You’ll have a small needle inserted into your arm or vein to draw blood. If you’re fasting, follow your provider’s instructions. Avoid smoking or caffeine before the test if advised, as it may affect results.

What Happens During the Test?

A healthcare professional will collect a blood sample from a vein in your arm. The sample is then sent to a lab for analysis. The process usually takes a few minutes, and you may feel a slight pinch or discomfort.

What the Results Mean

Results help determine if your bicarbonate levels are too high or too low, which can indicate conditions like metabolic acidosis or alkalosis. Your provider will discuss these findings in relation to your overall health and symptoms.

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

Serum/plasma bicarbonate

Frequently asked questions

How does bicarbonate relate to my overall health?
Bicarbonate is a critical buffer in your blood, helping maintain a stable pH. Low levels may signal metabolic acidosis (e.g., due to kidney problems or diabetes), while high levels could suggest metabolic alkalosis (e.g., from vomiting or overuse of antacids). Your provider will use these results alongside other tests to diagnose or monitor conditions affecting acid-base balance.
What if my bicarbonate level is out of range?
If your results are abnormal, your healthcare provider will review them with you and may recommend further testing or treatments, such as adjusting medications, managing fluid balance, or treating underlying conditions like kidney disease or respiratory issues.
Can lifestyle changes affect bicarbonate levels?
Yes, certain lifestyle factors like diet (e.g., high salt intake), dehydration, or excessive vomiting can influence bicarbonate levels. Avoiding excessive salt, staying hydrated, and following your provider’s advice for managing symptoms can help maintain balanced levels.
  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