Baseexoxystdbldccalcscnc
A blood test that measures the metabolic component of your body's acid-base balance.
{"Base excess shows how much acid your blood can neutralize","Positive values may indicate alkalosis (too alkaline)","Negative values may indicate acidosis (too acidic)","Helps doctors diagnose and monitor kidney, lung, and metabolic disorders","Usually measured along with other blood gas tests"}
Key facts at a glance
- LOINC
- 72720-6
- Short code
- Base ex.oxy std BldC Calc-sCnc
- Synonyms
- Base ex.oxy std BldC Calc-sCnc
- Category
- chemistry
- Sample
- whole-blood
- Container
- Lavender-top (EDTA)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- calculated
- 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 is this test?
The base excess test measures the amount of excess base (alkaline substances) in your blood. It evaluates the metabolic component of your acid-base balance, separate from how your lungs are affecting CO2 levels. This test is calculated from blood gas measurements taken from a capillary blood sample, typically from a finger prick or heel stick.
Why is it important?
Your body needs a precise balance between acids and bases (alkaline substances) to function properly. Base excess tells doctors whether your blood is too acidic (acidosis) or too alkaline (alkalosis) due to metabolic causes—not respiratory causes. This helps identify problems with kidney function, severe infections, poisoning, or metabolic disorders.
How is the test performed?
A healthcare provider will collect a small blood sample from your fingertip or heel (for infants). The blood is then analyzed in a laboratory using specialized equipment to calculate the base excess value. The test is often performed together with other blood gas tests like pH, pCO2, and oxygen levels.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Frequently asked questions
Do I need to fast before this test?
Is the test painful?
What do abnormal results mean?
How often will I need this test?
Sources
- 1
- 2
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 16, 2026. · Read our editorial policy