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Bicarbonate (HCO₃⁻) in Urine

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

This test measures the amount of bicarbonate, a key chemical in urine that helps balance acidity. It can help assess kidney function and acid-base balance.

Quick summary

["This test helps evaluate kidney health and urine acidity levels."]

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

Key facts at a glance

LOINC
47580-6
Short code
HCO3 24h Ur-sCnc
Synonyms
HCO3 24h Ur-sCnc
Category
chemistry
Sample
urine
Container
Sterile urine container
Units
N/A
Ref low
22
Ref high
28
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Specimen volume
10 mL
Stability
Room temperature: 2h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
0
Lipemia max
0
Icterus max
0
TAT
4–24 hours
Order
routine

Why Is This Test Done?

Your doctor may order this test if you have symptoms like frequent urination, kidney stones, or signs of metabolic issues. It can also help diagnose conditions affecting acid-base balance, such as kidney disease or certain metabolic disorders.

What Does the Result Mean?

Higher-than-normal levels might suggest conditions like kidney stones or certain metabolic disorders. Lower-than-normal levels could indicate problems with acid excretion or kidney function. Results are interpreted by your healthcare provider in the context of your overall health.

Sample Collection and Preparation

Urine for this test is typically collected in a clean container. You may be asked to provide a midstream urine sample or a 24-hour urine collection, depending on the test instructions. Always follow your healthcare provider’s instructions carefully.

Common Conditions Monitored

This test is often used to monitor kidney function, diagnose metabolic acidosis or alkalosis, and evaluate conditions like kidney stones, urinary tract infections, or metabolic disorders.

Reference range

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

Specimen: urine

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

Urine Bicarbonate

Frequently asked questions

What does a high urine bicarbonate level mean?
A high urine bicarbonate level may suggest conditions like kidney stones, certain metabolic disorders, or overcompensation of the body’s acid-base balance. Your doctor will review the result with other tests and symptoms to determine the cause.
How is urine collected for this test?
Urine is usually collected in a clean container. For a midstream sample, you cleanse the urinary tract before collecting a small amount of urine. For a 24-hour collection, you may need to collect all urine over a full day. Follow your healthcare provider’s specific instructions.
Can diet affect urine bicarbonate levels?
Yes, diet can influence urine bicarbonate levels. High intake of alkaline foods (like fruits and vegetables) or certain medications may increase bicarbonate levels. Avoiding excessive salt, caffeine, or alcohol may help stabilize results. Discuss dietary considerations with your doctor or healthcare team.
  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