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HelpTest Code ACRNS Acylcarnitines, Quantitative, Serum
Necessary Information
1. Patient's age is required.
2. Include family history, clinical condition (asymptomatic or acute episode), diet, and drug therapy information.
Specimen Required
Patient Preparation: Collect specimen just prior to a scheduled meal or feeding.
Collection Container/Tube:
Preferred: Serum gel
Acceptable: Red top
Submission Container/Tube: Plastic vial
Specimen Volume: 0.1 mL
Collection Instructions: Centrifuge and aliquot serum into plastic vial.
Useful For
Diagnosis of fatty acid oxidation disorders and several organic acidurias using serum specimens
Evaluating treatment during follow-up of patients with fatty acid beta-oxidation disorders and several organic acidurias
Method Name
Flow Injection Analysis-Tandem Mass Spectrometry (FIA-MS/MS)
Reporting Name
Acylcarnitines, Quantitative, SSpecimen Type
SerumSpecimen Minimum Volume
0.04 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Serum | Frozen (preferred) | 60 days | |
| Refrigerated | 21 days | ||
| Ambient | 72 hours |
Reject Due To
| Gross hemolysis | OK |
| Gross lipemia | OK |
| Gross icterus | OK |
Clinical Information
Acylcarnitine analysis enables the diagnosis of many disorders of fatty acid oxidation and several organic acidurias, as relevant enzyme deficiencies cause the accumulation of specific acyl-CoAs.(1) Fatty acid oxidation (FAO) plays a major role in energy production during periods of fasting. When the body's supply of glucose is depleted, fatty acids are mobilized from adipose tissue, taken up by the liver and muscles, and oxidized to acetyl-CoA. In the liver, acetyl-CoA is the building block for the synthesis of ketone bodies, which enter the blood stream and provide an alternative substrate for production of energy in other tissues when the supply of glucose is insufficient to maintain a normal level of energy. The acyl groups are conjugated with carnitine to form acylcarnitines, which can be measured by tandem mass spectrometry. Diagnostic results are usually characterized by a pattern of significantly elevated acylcarnitine species compared to normal and disease controls.
In general, more than 20 inborn errors of metabolism can be identified using this method including FAO disorders and organic acidurias. The major clinical manifestations associated with individual FAO disorders include hypoketotic hypoglycemia, variable degrees of liver disease or failure, skeletal myopathy, dilated/hypertrophic cardiomyopathy, and sudden or unexpected death. Organic acidurias also present as acute life-threatening events early in life with metabolic acidosis, increased anion gap, and neurologic distress. Patients with any of these disorders are at risk of developing fatal metabolic decompensations following the acquisition of even common infections. Once diagnosed, these disorders can be treated by avoidance of fasting, special diets, and cofactor/vitamin supplementation.
Additional confirmatory testing is recommended. The diagnosis of an underlying FAO disorder or organic aciduria allows genetic counseling of the family, including the possible option of future prenatal diagnosis, and testing of at-risk family members of any age.
The following disorders are detectable by acylcarnitine analysis. However, further confirmatory testing is required for most of these conditions because an acylcarnitine profile can be suggestive of more than one condition.
Fatty Acid Oxidation Disorders:
-Carnitine palmitoyltransferase I deficiency
-Medium-chain 3-ketoacyl-CoA thiolase deficiency
-Dienoyl-CoA reductase deficiency
-Short-chain acyl-CoA dehydrogenase deficiency
-Medium/Short-chain 3-hydroxyacyl-CoA dehydrogenase deficiency
-Medium-chain acyl-CoA dehydrogenase) deficiency
-Long-chain 3-hydroxyacyl-CoA dehydrogenase) deficiency and trifunctional protein deficiency
-Very long-chain acyl-CoA dehydrogenase deficiency
-Carnitine palmitoyl transferase type II deficiency
-Carnitine-acylcarnitine translocase deficiency
-Electron transfer flavoprotein (ETF) deficiency, ETF-dehydrogenase deficiency (multiple acyl-CoA dehydrogenase deficiency; glutaric acidemia type II)
Organic Acid Disorders:
-Glutaryl-CoA dehydrogenase deficiency (glutaric acidemia type I)
-Propionic acidemia
-Methylmalonic acidemia
-Isovaleric acidemia
-3-Hydroxy-3-methylglutaryl-CoA carboxylase deficiency
-3-Methylcrotonyl carboxylase deficiency
-Biotinidase deficiency
-Multiple carboxylase deficiency
-Isobutyryl-CoA dehydrogenase deficiency
-2-Methylbutyryl-CoA dehydrogenase deficiency
-Beta-ketothiolase deficiency
-Malonic aciduria
-Ethylmalonic encephalopathy
-Glutamate formiminotransferase deficiency (formiminoglutamic aciduria)
Reference Values
|
≤7 days (nmol/mL) |
8 days-7 years (nmol/mL) |
≥8 years (nmol/mL) |
|
|
Acetylcarnitine, C2 |
2.14-15.89 |
2.00-27.57 |
2.00-17.83 |
|
Acrylylcarnitine, C3:1 |
<0.04 |
<0.05 |
<0.07 |
|
Propionylcarnitine, C3 |
<0.55 |
<1.78 |
<0.88 |
|
Formiminoglutamate, FIGLU |
<0.43 |
<0.08 |
<0.14 |
|
Iso-/Butyrylcarnitine, C4 |
<0.46 |
<1.06 |
<0.83 |
|
Tiglylcarnitine, C5:1 |
<0.05 |
<0.09 |
<0.11 |
|
Isovaleryl-/2-Methylbutyrylcarn C5 |
<0.38 |
<0.63 |
<0.51 |
|
3-OH-iso-/butyrylcarnitine, C4-OH |
<0.13 |
<0.51 |
<0.18 |
|
Hexenoylcarnitine, C6:1 |
<0.12 |
<0.10 |
<0.15 |
|
Hexanoylcarnitine, C6 |
<0.14 |
<0.23 |
<0.17 |
|
3-OH-isovalerylcarnitine, C5-OH |
<0.08 |
<0.12 |
<0.10 |
|
Benzoylcarnitine |
<0.13 |
<0.07 |
<0.10 |
|
Heptanoylcarnitine, C7 |
<0.05 |
<0.05 |
<0.06 |
|
3-OH-hexanoylcarnitine, C6-OH |
<0.08 |
<0.19 |
<0.09 |
|
Phenylacetylcarnitine |
<0.15 |
<0.22 |
<0.29 |
|
Salicylcarnitine |
<0.08 |
<0.09 |
<0.09 |
|
Octenoylcarnitine, C8:1 |
<0.48 |
<0.91 |
<0.88 |
|
Octanoylcarnitine, C8 |
<0.19 |
<0.45 |
<0.78 |
|
Malonylcarnitine, C3-DC |
<0.09 |
<0.14 |
<0.26 |
|
Decadienoylcarnitine, C10:2 |
<0.11 |
<0.12 |
<0.26 |
|
Decenoylcarnitine, C10:1 |
<0.25 |
<0.46 |
<0.47 |
|
Decanoylcarnitine, C10 |
<0.27 |
<0.91 |
<0.88 |
|
Methylmalonyl-/succinylcarn, C4-DC |
<0.05 |
<0.05 |
<0.05 |
|
3-OH-decenoylcarnitine, C10:1-OH |
<0.12 |
<0.12 |
<0.13 |
|
Glutarylcarnitine, C5-DC |
<0.06 |
<0.10 |
<0.11 |
|
Dodecenoylcarnitine, C12:1 |
<0.19 |
<0.37 |
<0.35 |
|
Dodecanoylcarnitine, C12 |
<0.18 |
<0.35 |
<0.26 |
|
3-Methylglutarylcarnitine, C6-DC |
<0.28 |
<0.21 |
<0.43 |
|
3-OH-dodecenoylcarnitine, C12:1-OH |
<0.11 |
<0.10 |
<0.13 |
|
3-OH-dodecanoylcarnitine, C12-OH |
<0.06 |
<0.09 |
<0.08 |
|
Tetradecadienoylcarnitine, C14:2 |
<0.09 |
<0.13 |
<0.18 |
|
Tetradecenoylcarnitine, C14:1 |
<0.16 |
<0.35 |
<0.24 |
|
Tetradecanoylcarnitine, C14 |
<0.11 |
<0.15 |
<0.12 |
|
Octanedioylcarnitine, C8-DC |
<0.25 |
<0.19 |
<0.19 |
|
3-OH-tetradecenoylcarnitine C14:1OH |
<0.06 |
<0.18 |
<0.13 |
|
3-OH-tetradecanoylcarnitine, C14-OH |
<0.04 |
<0.05 |
<0.08 |
|
Hexadecenoylcarnitine, C16:1 |
<0.15 |
<0.21 |
<0.10 |
|
Hexadecanoylcarnitine, C16 |
<0.36 |
<0.52 |
<0.23 |
|
3-OH-hexadecenoylcarnitine,C16:1-OH |
<0.78 |
<0.36 |
<0.06 |
|
3-OH-hexadecanoylcarnitine, C16-OH |
<0.10 |
<0.07 |
<0.06 |
|
Octadecadienoylcarnitine, C18:2 |
<0.12 |
<0.31 |
<0.24 |
|
Octadecenoylcarnitine, C18:1 |
<0.25 |
<0.45 |
<0.39 |
|
Octadecanoylcarnitine, C18 |
<0.10 |
<0.12 |
<0.14 |
|
Dodecanedioylcarnitine, C12-DC |
<0.10 |
<0.04 |
<0.04 |
|
3-OH-octadecadienoylcarn, C18:2-OH |
<0.04 |
<0.06 |
<0.06 |
|
3-OH-octadecenoylcarnitine C18:1-OH |
<0.03 |
<0.04 |
<0.06 |
|
3-OH-octadecanoylcarnitine, C18-OH |
<0.03 |
<0.05 |
<0.03 |
Day(s) Performed
Monday through Friday
Report Available
2 to 5 daysPerforming Laboratory
Mayo Clinic Laboratories in Rochester
Test Classification
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.CPT Code Information
82017
Forms
If not ordering electronically, complete, print, and send a Biochemical Genetics Test Request (T798) with the specimen.