Baib24hursrate
This test measures the amount of beta-aminoisobutyric acid in a 24-hour urine collection to evaluate pyrimidine metabolism.
{"Measures beta-aminoisobutyric acid excreted in urine over 24 hours","Helps diagnose disorders of pyrimidine metabolism","Results may indicate genetic conditions, liver disease, or muscle disorders","Requires a complete 24-hour urine collection","Abnormal results need further medical evaluation"}
Key facts at a glance
- LOINC
- 25348-4
- Short code
- BAIBU24
- Synonyms
- B-AIB 24h Ur-sRate
- Category
- chemistry
- Sample
- urine
- Container
- 24-hour urine collection container with preservative (typically hydrochloric acid or thymol)
- Units
- N/A
- Ref low
- 4
- Ref high
- 20
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- Ion Exchange Chromatography or High-Performance Liquid Chromatography (HPLC)
- CPT
- 82139
- SNOMED
- 3952009
- Specimen volume
- Entire 24-hour urine collection; minimum 10 mL aliquot required for testing
- Stability
- Stable for 7 days at 2-8°C; for longer storage, freeze at -20°C
- Hemolysis max
- 0
- Lipemia max
- 0
- Icterus max
- 0
- TAT
- 72–168 hours
- Order
- routine
What is this test?
The beta-aminoisobutyrate test measures how much beta-aminoisobutyric acid (β-AIB) your kidneys excrete in urine over 24 hours. β-AIB is a byproduct of thymine (a DNA building block) metabolism. Normally, your body produces and breaks down this substance at a consistent rate, and the kidneys filter it into urine.
Why is this test performed?
This test helps doctors evaluate how your body metabolizes pyrimidines (one of the building blocks of DNA and RNA). It may be ordered when someone has symptoms suggesting a metabolic disorder, such as developmental delays, muscle weakness, or unexplained neurological problems. The test can also help identify certain inherited conditions affecting pyrimidine breakdown.
How to prepare for and collect the sample?
Your healthcare provider will give you specific instructions. Generally, you will receive a special container for collecting all urine over 24 hours. Start by emptying your bladder in the morning and note the time. Collect all urine for the next 24 hours, including the first morning urine on the second day. Keep the container refrigerated or on ice during collection. Return the container to the lab as instructed.
Understanding your results
Normal values vary by laboratory. Your doctor will interpret your results based on your age, sex, and medical history. Abnormal results (either high or low levels) do not necessarily mean you have a serious condition—your healthcare provider will determine if additional testing is needed.
Reference range
4.0-20.0 mg/24h (excretor phenotype dependent); 0-10 mg/24h for non-excretorsN/A
No special preparation required. Maintain usual diet and fluid intake unless otherwise directed. Collect all urine over the specified 24-hour period.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Frequently asked questions
Is this test painful?
How long does the collection take?
Can I exercise during the collection period?
What happens if I miss a urine sample during collection?
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