Acylcarnitine24hursrate
A 24-hour urine test that measures acylcarnitine levels to help diagnose metabolic disorders affecting how your body breaks down fats for energy.
{"This test checks for rare metabolic disorders that affect energy production from fats","A 24-hour urine collection is required - you will receive a special container","Abnormal results may indicate conditions like fatty acid oxidation disorders or organic acidemias","Follow all collection instructions carefully for accurate results","Your healthcare provider will discuss what your specific results mean for your situation"}
Key facts at a glance
- LOINC
- 34227-9
- Short code
- ACRN24
- Synonyms
- Acylcarnitine 24h Ur-sRate
- Category
- chemistry
- Sample
- urine
- Container
- Plastic urine container (24-hour collection container), no preservative required
- Units
- N/A
- Ref low
- 100
- Ref high
- 600
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 0–120 years
- Method
- Tandem Mass Spectrometry (MS/MS)
- CPT
- 82017
- SNOMED
- 314252001
- Specimen volume
- Aliquot: 1-2 mL from well-mixed 24-hour collection; submit entire volume if small
- Stability
- Room temperature: 24 hours; Refrigerated (2-8°C): 7 days; Frozen (-20°C or below): 30 days
- Hemolysis max
- 0
- Lipemia max
- 0
- Icterus max
- 0
- TAT
- 72–168 hours
- Order
- routine
What is this test?
The acylcarnitine test measures the amount of acylcarnitine in your urine. Acylcarnitines are substances produced when carnitine (a compound derived from food) binds to fatty acids or organic acids. This process is important because it helps transport these substances into cells where they can be used for energy.
Why do I need this test?
Your doctor may order this test if they suspect a metabolic disorder, especially if you or your child has symptoms such as unexplained fatigue, muscle weakness, low blood sugar, vomiting, or developmental delays. This test helps identify conditions where the body cannot properly break down fats for energy, which are often genetic conditions present from birth.
How is the sample collected?
For a 24-hour urine test, you will collect all urine you produce over a 24-hour period. You will receive a special container from the lab. On the first day, start by emptying your bladder in the morning and noting the time. Then collect all urine for the rest of that day and night, and the first morning urine of the next day at the same time you started. Keep the container refrigerated or in a cool place during collection. Label the container with your name, date of birth, and the start and end times of collection.
Are there any risks?
This is a routine urine test with no known risks. The main challenge is collecting the sample correctly over the 24-hour period. Follow all instructions provided by your healthcare team to ensure accurate results.
Reference range
Reference ranges vary by specific acylcarnitine species. Typical 24-hour urine excretion for total acylcarnitines: 100-600 umol/24h. Individual acylcarnitine fractions (e.g., C0, C2, C3, C4, C5, C8, C14, C16) have specific reference intervals. Consult laboratory-specific reference ranges for interpretation.N/A
Collect 24-hour urine in provided container. Begin collection after first morning void; collect all urine for the next 24 hours. Store container in cool place during collection. Return completed collection to laboratory promptly. Avoid contamination with feces or foreign objects.
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?
What happens if I miss a urine sample during the 24-hour collection?
How long will it take to get results?
Is this test only for children?
What do abnormal results mean?
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