Understanding Your Laboratory Test: A Complete Patient Guide to What It Is, Why It Is Done, and How to Read Your Results
Acylcarnitine testing is a blood test that checks for specific metabolic substances to help diagnose inherited fatty acid oxidation disorders and organic acidemias.
{"This test measures acylcarnitine levels in blood to detect metabolic disorders","It is commonly used in newborn screening programs","Abnormal results may indicate problems with how the body converts fat into energy","Early detection helps prevent serious health complications","The test requires a simple blood draw"}
Key facts at a glance
- LOINC
- 43715-2
- Short code
- ACYL
- Synonyms
- Acylcarnitine Bld Ql
- Category
- chemistry
- Sample
- whole-blood
- Container
- Dried Blood Spot (DBS) card (filter paper) or EDTA (lavender top) whole blood tube
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- ≥ 0 years
- Method
- Tandem Mass Spectrometry (MS/MS) or Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)
- CPT
- 82017
- SNOMED
- 313334005
- Specimen volume
- DBS: One full spot (approximately 50-100 μL blood); Whole blood: 1-3 mL in EDTA tube
- Stability
- DBS: Stable at room temperature (15-25°C) for 7-10 days, refrigerated (2-8°C) for 2-3 weeks, frozen (-20°C or below) for longer; Whole blood: Refrigerate within 24 hours, stable 72 hours at 2-8°C
- Hemolysis max
- 0
- Lipemia max
- 0
- Icterus max
- 0
- TAT
- 24–72 hours
- Order
- routine
This test is a laboratory examination that measures specific substances in a sample taken from your body, most often blood, urine, or other body fluids. It provides your doctor with objective information about how your organs and body systems are working.
The acylcarnitine test is a blood test that measures the presence and amount of acylcarnitines in your blood. Acylcarnitines are substances produced when your body breaks down fatty acids for energy. This test helps doctors detect certain inherited metabolic disorders that affect how the body processes fats.
Your doctor may order this test to help diagnose a medical condition, check how well a treatment is working, screen for disease before symptoms appear, or monitor an ongoing health problem over time.
Doctors order this test primarily to: (1) Screen newborns for metabolic disorders as part of routine newborn screening programs, (2) Diagnose suspected metabolic disorders when symptoms such as muscle weakness, low blood sugar, or developmental delays are present, (3) Monitor patients already diagnosed with fatty acid oxidation disorders, and (4) Evaluate family members of individuals with known metabolic conditions.
The test is usually done by collecting a small sample at a clinic, hospital, or laboratory. A trained professional will draw blood from a vein in your arm or ask you to provide a urine sample, and the sample is then sent for analysis.
A healthcare professional will collect a small blood sample from a vein in your arm or, for newborns, from a heel stick. The blood is then sent to a laboratory where special equipment measures the different types of acylcarnitines present. The test is safe and takes only a few minutes to collect the sample.
Your results show whether your values fall within the normal reference range printed on your report. Normal results generally suggest no concern, while abnormal values may point to a condition that needs further evaluation, so always review them with your doctor.
Normal results mean no abnormal levels of acylcarnitines were detected. Abnormal results may indicate a metabolic disorder such as Medium-chain acyl-CoA dehydrogenase deficiency (MCAD), Carnitine palmitoyltransferase (CPT) deficiency, or various organic acidemias. Your doctor will interpret the specific patterns of acylcarnitine elevation to determine which condition, if any, may be present.
Reference range
Not detected / Negative - Normal acylcarnitine profileN/A
No special preparation required. Inform the laboratory of any medications, supplements, or nutritional status as these may affect results. For newborns, specimen should be collected prior to feeding or at any routine time.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
The acylcarnitine test is crucial for detecting fatty acid oxidation disorders, which are inherited conditions where the body cannot properly break down fats for energy. These disorders can lead to serious complications including hypoglycemia (low blood sugar), muscle damage, heart problems, and developmental delays if not treated early. The test is especially important in newborns because early detection through screening allows for early intervention with special diets and medications that can prevent life-threatening complications. Treatment typically involves dietary modifications, avoiding fasting, and sometimes carnitine supplementation under medical supervision.
Frequently asked questions
Is fasting required before this test?
Are there any risks with this test?
How long does it take to get results?
What happens if my results are abnormal?
Can adults have this test?
Sources
- 1
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- 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 16, 2026. · Read our editorial policy