Test ID: ACRN
Acylcarnitines, Quantitative, Plasma
Secondary ID 
A test code used for billing and in test definitions created prior to November 2011
NY State Approved Indicates the status of NY State approval and if the test is orderable for NY State clients.
Useful For Suggests clinical disorders or settings where the test may be helpful
Diagnosis of fatty acid oxidation disorders and several organic acidurias
Evaluating treatment during follow-up of patients with fatty acid beta-oxidation disorders and several organic acidurias
Testing Algorithm Delineates situation(s) when tests are added to the initial order. This includes reflex and additional tests.
The following algorithms are available in Special Instructions:
-Newborn Screening Follow-up for Elevations of C8, C6, and C10 Acylcarnitines (also applies to any plasma C8, C6, and C10 acylcarnitine elevations)
-Newborn Screening Follow-up for Isolated C4 Acylcarnitine Elevations (also applies to any plasma C4 acylcarnitine elevation)
-Newborn Screening Follow-up for Isolated C5 Acylcarnitine Elevations (also applies to any plasma C5 acylcarnitine elevation)
Special Instructions and Forms Describes specimen collection and preparation information, test algorithms, and other information pertinent to test. Also includes pertinent information and consent forms to be used when requesting a particular test
- Newborn Screening Follow-up for Isolated C4 Acylcarnitine Elevations (also applies to any plasma C4 acylcarnitine elevations)
- Newborn Screening Follow-up for Elevations of C8, C6, and C10 Acylcarnitine (also applies to any plasma C8, C6, and C10 acylcarnitine elevations)
- Newborn Screening Follow-up for Isolated C5 Acylcarnitines Elevations (also applies to any plasma C5 acylcarnitine elevation)
Method Name A short description of the method used to perform the test
Flow Injection Analysis-Tandem Mass Spectrometry (FIA-MS/MS)
Reporting Name A shorter/abbreviated version of the Published Name for a test; an abbreviated test name
Aliases Lists additional common names for a test, as an aid in searching
3-Methylcrotonyl Carboxylase Deficiency
Biotinidase (Multiple Carboxylase) Deficiency
CPT-II (Carnitine Palmitoyl Transferase Deficiency Type II)
Electron-Transfer Flavoprotein (ETF) Deficiency
Glutaric Acidemia (GA)
Glutaric Acidemia Type I (GA I)
Glutaric Acidemia Type II (GA II)
Glutaryl-CoA Dehydrogenase (GCDH) Deficiency
Isobutyryl-CoA Dehdrogenase (IBDH) Deficiency
Isovaleric Acidemia (IVA)
Long-Chain 3-Hydroxyacyl-CoA Dehydrogenase (LCHAD) Deficiency
MADD (Multiple Acyl-CoA Dehydrogenase Deficiency)
Malonic aciduria
Medium-Chain Acyl-CoA Dehydrogenase (MCAD) Deficiency
Methylmalonic Acidemia
Methylmalonic Aciduria (MMA)
Multiple Acyl-CoA Dehydrogenase Deficiency (MADD)
S/MCHAD (Short/Medium-Chain 3-Hydroxyacyl-CoA Dehydrogenase) Deficiency
SCAD (Short-Chain Acyl-CoA Dehydrogenase) Deficiency
Short/Medium-Chain 3-Hydroxyacyl-CoA Dehydrogenase (S/MCHAD) Deficiency
Trifunctional Protein (TFP) Deficiency
Very Long-Chain Acyl-CoA Dehydrogenase (VLCAD) Deficiency
2-Methyl-3-hydroxybutyryl CoA Dehydrogenase Deficiency
3-Hydroxy-3-Methylglutaryl-CoA (HMG-CoA) Lyase Deficiency
3-Methylglutaconyl-CoA Hydratase Deficiency
Beta-ketothiolase Deficiency
Carnitine-acylcarnitine Translocase (CACT) Deficiency
Formiminoglutamic Aciduria (FIGLU)
Formiminotransferase (FIGLU) Deficiency
Holocarboxylase Synthetase Deficiency
Succinyl-CoA Ligase (SUCLA2) Deficiency
SUCLA2 (Succinyl-CoA Ligase) Deficiency
3-Methylglutaconic Aciduria Type I
3-Methylglutaconic Aciduria Type 1
Propionic Acidemia (PA)
Specimen Type Describes the specimen type needed for testing
Specimen Required Defines the optimal specimen. This field describes the type of specimen required to perform the test and the preferred volume to complete testing. The volume allows automated processing, fastest throughput and, when indicated, repeat or reflex testing.
Specimen Type: Plasma
Collection Container/Tube:
Preferred: Green top (sodium heparin)
Acceptable: Lavender top (EDTA)
Submission Container/Tube: Plastic vial
Specimen Volume: 0.1 mL
Collection Instructions: Draw specimen just prior to a scheduled meal or feeding.
Additional Information:
1. Patient's age is required.
2. Include family history, clinical condition (asymptomatic or acute episode), diet, and drug therapy information.
Forms: If not ordering electronically, submit a Biochemical Genetics Request Form (Supply T439) with the specimen.
Specimen Minimum Volume Defines the amount of specimen required to perform an assay once, including instrument and container dead space. Submitting the minimum specimen volume makes it impossible to repeat the test or perform confirmatory or perform reflex testing. In some situations, a minimum specimen volume may result in a QNS (quantity not sufficient) result, requiring a second specimen to be collected.
Reject Due To Identifies specimen types and conditions that may cause the specimen to be rejected
| Hemolysis | Mild OK; Gross OK |
| Lipemia | Mild OK; Gross OK |
| Icterus | Mild OK; Gross OK |
| Other | NA |
Specimen Stability Information Provides a description of the temperatures required to transport a specimen to the laboratory. Alternate acceptable temperature(s) are also included.
| Specimen Type | Temperature | Time |
|---|---|---|
| Varies | Frozen (preferred) | 92 days |
| Refrigerated | 64 days | |
| Ambient | 8 days |
Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
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. 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 are measured by tandem mass spectrometry (MS/MS). 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 and/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 viral infections. Once diagnosed, these disorders can be treated by avoidance of fasting, special diets, and cofactor/vitamin supplementation.
Analysis of acylcarnitines in blood and bile spots represents the first level of evaluation of a complete postmortem investigation of a sudden or unexpected death of an individual. 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.
Disorders Detectable by Acylcarnitine Analysis*
Fatty Acid Oxidation Disorders:
-Short-chain acyl-CoA dehydrogenase (SCAD) deficiency
-Medium/Short-chain 3-hydroxyacyl-CoA dehydrogenase (M/SCHAD) deficiency
-Medium-chain acyl-CoA dehydrogenase (MCAD) deficiency
-Long-chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD) deficiency & trifunctional protein deficiency
-Very long-chain acyl-CoA dehydrogenase (VLCAD) deficiency
-Carnitine palmitoyl transferase type II (CPT-II) deficiency
-Carnitine-acylcarnitine translocase (CACT) deficiency
-Electron transfer flavoprotein (ETF) deficiency, ETF-dehydrogenase deficiency (multiple acyl-CoA dehydrogenase deficiency [MADD]; 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
*Further confirmatory testing is required for most of these conditions because an acylcarnitine profile can be suggestive of more than 1 condition.
Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.
Acetylcarnitine, C2
1-7 days: 2.14-15.89 nmol/mL
8 days-7 years: 2.00-27.57 nmol/mL
> or =8 years: 2.00-17.83 nmol/mL
Propionylcarnitine, C3
1-7 days: <0.55 nmol/mL
8 days-7 years: <1.78 nmol/mL
> or =8 years: <0.88 nmol/mL
Iso-/Butyrylcarnitine, C4
1-7 days: <0.46 nmol/mL
8 days-7 years: <1.06 nmol/mL
> or =8 years: <0.83 nmol/mL
Isovaleryl-/2-Methylbutyrylcarnitine, C5
1-7 days: <0.38 nmol/mL
8 days-7 years: <0.63 nmol/mL
> or =8 years: <0.51 nmol/mL
Hexanoylcarnitine, C6
1-7 days: <0.14 nmol/mL
8 days-7 years: <0.23 nmol/mL
> or =8 years: <0.17 nmol/mL
3-OH-Hexanoylcarnitine, C6-OH
1-7 days: <0.08 nmol/mL
8 days-7 years: <0.19 nmol/mL
> or =8 years: <0.09 nmol/mL
Octenoylcarnitine, C8:1
1-7 days: <0.48 nmol/mL
8 days-7 years: <0.91 nmol/mL
> or =8 years: <0.88 nmol/mL
Octanoylcarnitine, C8
1-7 days: <0.19 nmol/mL
8 days-7 years: <0.45 nmol/mL
> or =8 years: <0.78 nmol/mL
Decenoylcarnitine, C10:1
1-7 days: <0.25 nmol/mL
8 days-7 years: <0.46 nmol/mL
> or =8 years: <0.47 nmol/mL
Decanoylcarnitine, C10
1-7 days: <0.27 nmol/mL
8 days-7 years: <0.91 nmol/mL
> or =8 years: <0.88 nmol/mL
Glutarylcarnitine, C5-DC
1-7 days: <0.06 nmol/mL
8 days-7 years: <0.10 nmol/mL
> or =8 years: 0.11 nmol/mL
Dodecenoylcarnitine, C12:1
1-7 days: <0.19 nmol/mL
8 days-7 years: <0.37 nmol/mL
> or =8 years: <0.35 nmol/mL
Dodecanoylcarnitine, C12
1-7 days: <0.18 nmol/mL
8 days-7 years: <0.35 nmol/mL
> or =8 years: <0.26 nmol/mL
3-OH-Dodecanoylcarnitine, C12-OH
1-7 days: <0.06 nmol/mL
8 days-7 years: <0.09 nmol/mL
> or =8 years: <0.08 nmol/mL
Tetradecadienoylcarnitine, C14:2
1-7 days: <0.09 nmol/mL
8 days-7 years: <0.13 nmol/mL
> or =8 years: <0.18 nmol/mL
Tetradecenoylcarnitine, C14:1
1-7 days: <0.16 nmol/mL
8 days-7 years: <0.35 nmol/mL
> or =8 years: <0.24 nmol/mL
Tetradecanoylcarnitine, C14
1-7 days: <0.11 nmol/mL
8 days-7 years: <0.15 nmol/mL
> or =8 years: <0.12 nmol/mL
3-OH-Tetradecenoylcarnitine, C14:1-OH
1-7 days: <0.06 nmol/mL
8 days-7 years: <0.18 nmol/mL
> or =8 years: <0.13 nmol/mL
3-OH-Tetradecanolycarnitine, C14-OH
1-7 days: <0.04 nmol/mL
8 days-7 years: <0.05 nmol/mL
> or =8 years: <0.08 nmol/mL
Hexadecenoylcarnitine, C16:1
1-7 days: <0.15 nmol/mL
8 days-7 years: <0.21 nmol/mL
> or =8 years: <0.10 nmol/mL
Hexadecanoylcarnitine, C16
1-7 days: <0.36 nmol/mL
8 days-7 years: <0.52 nmol/mL
> or =8 years: <0.23 nmol/mL
3-OH-Hexadecenoylcarnitine, C16:1-OH
1-7 days: <0.78 nmol/mL
8 days-7 years: <0.36 nmol/mL
> or =8 years: <0.06 nmol/mL
3-OH-Hexadecanoylcarnitine, C16-OH
1-7 days: <0.10 nmol/mL
8 days-7 years: <0.07 nmol/mL
> or =8 years: <0.06 nmol/mL
Linoleylcarnitine, C18:2
1-7 days: <0.12 nmol/mL
8 days-7 years: <0.31 nmol/mL
> or =8 years: <0.24 nmol/mL
Oleylcarnitine, C18:1
1-7 days: <0.25 nmol/mL
8 days-7 years: <0.45 nmol/mL
> or =8 years: <0.39 nmol/mL
Stearoylcarnitine, C18
1-7 days: <0.10 nmol/mL
8 days-7 years: <0.12 nmol/mL
> or =8 years: <0.14 nmol/mL
3-OH-Linoleylcarnitine, C18:2-OH
1-7 days: <0.04 nmol/mL
8 days-7 years: <0.06 nmol/mL
> or =8 years: <0.06 nmol/mL
3-OH-Oleylcarnitine, C18:1-OH
1-7 days: <0.03 nmol/mL
8 days-7 years: <0.04 nmol/mL
> or =8 years: <0.06 nmol/mL
Interpretation Provides information to assist in interpretation of the test results
An interpretive report is provided. The individual quantitative results support the interpretation of the acylcarnitine profile but are not diagnostic by themselves. The interpretation is based on pattern recognition.
Abnormal results are not sufficient to conclusively establish a diagnosis of a particular disease. To verify a preliminary diagnosis based on an acylcarnitine analysis, independent biochemical (eg, in vitro enzyme assay) or molecular genetic analyses are required.
For information on the follow-up of specific acylcarnitine elevations, see Special Instructions for the following algorithms:
-Newborn Screening Follow-up for Elevations of C8, C6, and C10 Acylcarnitines (also applies to any plasma C8, C6, and C10 acylcarnitine elevations)
-Newborn Screening Follow-up for Isolated C4 Acylcarnitine Elevations (also applies to any plasma C4 acylcarnitine elevation)
-Newborn Screening Follow-up for Isolated C5 Acylcarnitine Elevations (also applies to any plasma C5 acylcarnitine elevation)
Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
In a few instances, false-negative results occur in the analysis of acylcarnitine profiles. For some disorders, such as medium-chain acyl-CoA dehydrogenase (MCAD) deficiency, the calculation of ratios between different acylcarnitine species provides a discriminate factor to overcome such problems. Where applicable, the calculation of such ratios will be incorporated in the routine acylcarnitine analysis. Informative profiles may also not be detected in some disorders where the accumulation of diagnostic acylcarnitines is a reflection of the residual activity of the defective enzyme, the dietary load of precursors, and the anabolic/catabolic and treatment status of a patient.
Patients with carnitine deficiency may not exhibit abnormally high acylcarnitine concentrations. If the results are indicative for carnitine deficiency, the interpretation will include a remark that this limits the diagnostic value of the test and repeat analysis may be considered following carnitine supplementation.
Follow-up testing such as in vitro enzyme assays or molecular genetic testing may be recommended following abnormal acylcarnitine results. It is not advisable to intentionally stress the patient's metabolism (eg, fasting test) prior to specimen collection for acylcarnitine analysis.
Clinical Reference Provides recommendations for further in-depth reading of a clinical nature
1. Matern D: Acylcarnitines, including in vitro loading tests. In Laboratory Guide to the Methods in Biochemical Genetics. Edited by N Blau, M Duran, KM Gibson. Springer Verlag 2008 pp 171-206
2. Rinaldo P, Cowan TM, Matern D: Acylcarnitine profile analysis. Genet Med 2008;10:151-156
3. Smith EH, Matern D: Acylcarnitine analysis by tandem mass spectrometry. Curr Protoc Hum Genet. 2010;Chapter 17:Unit 17.8.1-20
Method Description Describes how the test is performed and provides a method-specific reference
To 20 microL of plasma, 6 internal standards of known concentration (d3-acetylcarnitine, d3-propionylcarnitine, d7-butyrylcarnitine, d3-octanoylcarnitine, d3-dodecanoylcarnitine, and d3-palmitoyl-carnitine) and acetonitrile for deproteinization are added. Following shaking for 30 minutes and centrifugation, the supernate is dried and then treated with n-butanolic HCl yielding the acylcarnitines, which are analyzed as their n-butylesters by electrospray ionization tandem mass spectrometry. The concentrations of the analytes are established by computerized comparison of these analytes' ion intensities to those of the closest internal standard. (Van Hove JL, Kahler SG, Feezor MD, et al: Acylcarnitines in plasma and blood spots of patients with long-chain 3-hydroxyacylcoenzyme A dehydrogenase deficiency. J Inherit Metab Dis 2000;23:571-582)
Day(s) and Time(s) Test Performed Outlines the days and times the test is performed. This field reflects the day and time the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time required before the test is performed. Some tests are listed as continuously performed, which means assays are performed several times during the day.
Monday through Friday
Analytic Time Defines the amount of time it takes the laboratory to setup and perform the test. This is defined in number of days. The shortest interval of time expressed is "same day/1 day," which means the results may be available the same day that the sample is received in the testing laboratory. One day means results are available 1 day after the sample is received in the laboratory.
Maximum Laboratory Time Defines the maximum time from specimen receipt at Mayo Medical Laboratories until the release of the test result
Specimen Retention Time Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded
Performing Laboratory Location The location of the laboratory that performs the test
Test Classification Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer's instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR), Investigation Use Only (IUO) product, or a Research Use Only (RUO) product.
CPT Code Information Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Medical Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.
82017
LOINC® Code Information Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the result codes returned for this test or profile.
| Result ID | Reporting Name | LOINC Code |
|---|---|---|
| 82413 | Acylcarnitines, Quantitative, P | 46252-3 |
| 10288 | Acetylcarnitine, C2 | 30191-1 |
| 10289 | Propionylcarnitine, C3 | 30551-6 |
| 10290 | Iso-/Butyrylcarnitine, C4 | 43243-5 |
| 10293 | Isovaleryl-/2-Methylbutyrylcarn C5 | 30531-8 |
| 10295 | Hexanoylcarnitine, C6 | 30358-6 |
| 10297 | 3-OH-hexanoylcarnitine, C6-OH | 30236-4 |
| 10298 | Octenoylcarnitine, C8:1 | 30541-7 |
| 10299 | Octanoylcarnitine, C8 | 30540-9 |
| 10301 | Decenoylcarnitine, C10:1 | 30328-9 |
| 10302 | Decanoylcarnitine, C10 | 30327-1 |
| 10304 | Glutarylcarnitine, C5-DC | 30349-5 |
| 10305 | Dodecenoylcarnitine, C12:1 | 30332-1 |
| 10306 | Dodecanoylcarnitine, C12 | 30331-3 |
| 10307 | 3-OH-dodecanoylcarnitine, C12-OH | 30233-1 |
| 10308 | Tetradecadienoylcarnitine, C14:2 | 30564-9 |
| 10309 | Tetradecenoylcarnitine, C14:1 | 30566-4 |
| 10310 | Tetradecanoylcarnitine, C14 | 30565-6 |
| 10311 | 3-OH-tetradecenoylcarnitine C14:1OH | 30190-3 |
| 10312 | 3-OH-tetradecanoylcarnitine, C14-OH | 30238-0 |
| 10313 | Hexadecenoylcarnitine, C16:1 | 30357-8 |
| 10314 | Hexadecanoylcarnitine, C16 | 30356-0 |
| 10315 | 3-OH-hexadecenoylcarnitine,C16:1-OH | 30235-6 |
| 10316 | 3-OH-hexadecanoylcarnitine, C16-OH | 30234-9 |
| 10317 | Linoleylcarnitine, C18:2 | 30534-2 |
| 10318 | Oleylcarnitine, C18:1 | 30542-5 |
| 10319 | Stearoylcarnitine, C18 | 30560-7 |
| 10320 | 3-OH-linoleylcarnitine, C18:2-OH | 30237-2 |
| 10321 | 3-OH-oleylcarnitine, C18:1-OH | 30312-3 |
| 10322 | Comment | 48767-8 |
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