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Acylcarnitineserplscnc

Published: August 9, 2026Updated: August 10, 2026

Acylcarnitine test measures specific substances in blood to screen for inherited metabolic disorders that affect how the body processes fats for energy.

Quick summary

{"Acylcarnitine test helps detect genetic metabolic disorders, especially in newborns","It measures acylcarnitine levels produced when the body breaks down fatty acids","Abnormal results may indicate conditions like MCAD deficiency or carnitine deficiency","The test is commonly used for newborn screening but also helps diagnose metabolic issues in adults","Early detection through this test can prevent serious complications with proper treatment"}

Medically reviewed by WellAlly Editorial TeamLast reviewed August 10, 2026Editorial policy

Key facts at a glance

LOINC
14282-8
Short code
ACY
Synonyms
Acylcarnitine SerPl-sCnc
Category
chemistry
Sample
serum
Container
Serum separator tube (SST) or plain red top tube
Units
N/A
Ref low
20
Ref high
60
Fasting
false
Population
adult
Sex
all
Age range
0–120 years
Method
Tandem Mass Spectrometry (MS/MS)
CPT
82017
SNOMED
314382006
Specimen volume
0.5-1.0 mL serum minimum
Stability
Room temperature: 24 hours; Refrigerated (2-8°C): 7 days; Frozen (-20°C or below): 30 days. Avoid repeated freeze-thaw cycles.
Hemolysis max
50
Lipemia max
300
Icterus max
20
TAT
48–168 hours
Order
routine

What is this test?

The acylcarnitine test measures the levels of acylcarnitines in your blood. Acylcarnitines are substances produced when your body breaks down fatty acids for energy. This test is primarily used to screen for and diagnose inherited metabolic disorders that affect how the body converts fat into energy.

Why is it performed?

This test is performed for several important reasons: (1) Newborn screening - almost all newborns are tested within the first few days of life to detect potentially serious metabolic disorders early; (2) Diagnostic testing - when symptoms suggest a metabolic disorder such as unexplained muscle weakness, low blood sugar, or heart problems; (3) Monitoring - to track treatment effectiveness in patients already diagnosed with metabolic disorders; (4) Family testing - to check other family members if a genetic disorder is identified.

What do the results mean?

Results show different types (profiles) of acylcarnitines. Each pattern may indicate specific disorders. Elevated levels of certain acylcarnitines can suggest conditions like medium-chain acyl-CoA dehydrogenase deficiency (MCAD), primary carnitine deficiency, or other fatty acid oxidation disorders. Your healthcare provider will interpret results based on your specific situation, including symptoms, medical history, and other test findings.

How is the test done?

A small blood sample is taken from a vein in your arm (for adults and children) or from a heel stick (for newborns). The sample is then sent to a laboratory where specialized equipment measures the acylcarnitine levels. The test is safe with minimal risks, similar to routine blood tests - you may experience slight bruising or soreness at the needle site.

Reference range

Reference ranges vary by specific acylcarnitine species measured. Typical reference ranges for total acylcarnitine: 20-60 μmol/L. Specific species include: Free carnitine (C0): 25-50 μmol/L, Acetylcarnitine (C2): 5-20 μmol/L, Propionylcarnitine (C3): <5 μmol/L, Isovalerylcarnitine (C5): <1 μmol/L. Results should be interpreted in context of clinical presentation and follow-up testing.N/A

Specimen: serum

No special preparation required. Test can be performed without fasting, though some laboratories may prefer fasting samples for certain acylcarnitine species to reduce postprandial interference.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Frequently asked questions

Is fasting required before the test?
For newborns, fasting is not required as the test is part of routine screening. For older children and adults, your doctor may recommend fasting for 8-12 hours before the test, as eating can temporarily affect acylcarnitine levels. Always follow your healthcare provider's specific instructions.
What happens if the test is abnormal?
An abnormal result does not always mean your baby or you have a serious condition. Sometimes abnormal results can be due to other factors like prematurity or sampling issues. If the initial test is abnormal, repeat testing and additional evaluations will be done to confirm a diagnosis. If a disorder is confirmed, specialists in metabolic disorders will provide guidance on treatment and management.
Can adults have this test?
Yes, adults can have this test if they show symptoms of metabolic disorders or if a family member has been diagnosed with a fatty acid oxidation disorder. Symptoms in adults may include muscle pain, weakness, heart problems, or episodes of low blood sugar.
Is treatment available if a disorder is found?
Yes, most fatty acid oxidation disorders are manageable with proper treatment. Treatment typically includes dietary modifications (such as avoiding fasting, special low-fat diets), carnitine supplementation (for certain disorders), and careful management during illness. With early detection and proper treatment, many individuals with these disorders can live relatively normal, healthy lives.
Will this test affect my insurance or my child's future?
In many countries, newborn screening results are protected health information. In the United States, the Newborn Screening Saves Lives Act provides some protections, and most states have laws regarding the use of newborn screening results. Discuss any concerns with your healthcare provider or a genetic counselor who can explain the specific regulations in your area.
  1. 1
    MedlinePlus - Newborn ScreeningSource
  2. 2
    Mayo Clinic - Metabolic Disorder ScreeningSource
  3. 3
    National Institutes of Health - Fatty Acid Oxidation DisordersSource

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.

Medical Disclaimer

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 10, 2026. · Read our editorial policy