Bicarbonate (HCO₃⁻) in Urine
This test measures the amount of bicarbonate, a key buffer in your urine, which helps balance acidity. It can help assess kidney function and metabolic health.
["This test helps evaluate how well your kidneys remove acid from your body through urine."]
Key facts at a glance
- LOINC
- 1964-6
- Short code
- HCO3 Ur-sCnc
- Synonyms
- HCO3 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 healthcare provider may order this test if you have symptoms like frequent urination, kidney stones, metabolic acidosis (too much acid in your body), or if they suspect a condition affecting your kidneys or acid-base balance.
What Does a Low or High Level Mean?
Low bicarbonate levels in urine might indicate problems with kidney function, such as kidney stones or certain metabolic disorders. High levels could suggest conditions like kidney disease or overuse of certain medications.
How Is This Test Performed?
A urine sample is collected, typically during a 24-hour period, and sent to a lab for analysis. The lab measures the concentration of bicarbonate in the urine using standard laboratory techniques.
What Are Common Causes?
Common causes of abnormal bicarbonate levels in urine include kidney diseases (like chronic kidney disease), metabolic acidosis, certain medications, or conditions affecting urine concentration.
Reference range
NCBI: HCO3- 22-28 mmol/LN/A
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: Bicarbonate in urine can reflect kidney function and acid-base balance. Low levels may signal impaired kidney ability to excrete acid, while high levels could indicate overcompensation for metabolic issues or kidney dysfunction. This test is often part of a broader evaluation for conditions like kidney stones, metabolic disorders, or acid-base imbalances.
Short name
Urine Bicarbonate
Frequently asked questions
What does a normal urine bicarbonate level mean for my health?
Can diet affect urine bicarbonate levels?
How often should I get this test?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
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.
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