Baseexcessfldnbcalcscnc
A calculation test that measures the base excess in nonbiological fluid to help evaluate acid-base balance in the body.
{"Base excess measures the amount of excess acid or base in the blood","Positive values indicate metabolic alkalosis, negative values indicate metabolic acidosis","This test uses serum sample for analysis","Results help doctors diagnose and monitor acid-base balance disorders","The test is performed by calculation rather than direct measurement"}
Key facts at a glance
- LOINC
- 53085-7
- Short code
- Base excess Fld.NB Calc-sCnc
- Synonyms
- Base excess Fld.NB Calc-sCnc
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- calculated
- Specimen volume
- 5 mL
- Stability
- Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 4–24 hours
- Order
- routine
What is this test?
The Base Excess test measures the amount of acid or base in the blood. Base excess (BE) is a calculated value that indicates how much acid or base is needed to return the blood pH to normal. A positive base excess means there is too much base (alkali) in the blood, while a negative base excess means there is too much acid. This test uses serum as the sample type and is performed through calculation rather than direct measurement.
How is the test performed?
A blood sample is collected from a vein in your arm. The sample is then sent to a laboratory where the base excess value is calculated using specialized formulas that consider various blood parameters. The test is part of arterial blood gas analysis but can also be derived from venous blood samples.
What do the results mean?
Normal base excess values typically range from -2 to +2 mEq/L. A result of 0 means your blood pH is balanced. Positive values (above +2) may indicate metabolic alkalosis, which can be caused by conditions like prolonged vomiting, diuretic use, or certain kidney disorders. Negative values (below -2) may indicate metabolic acidosis, which can result from conditions like kidney failure, diabetic ketoacidosis, or lactic acidosis.
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 this test painful?
How long does it take to get results?
What can cause abnormal base excess values?
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