Test Id : FAO
Fatty Acid Oxidation Probe Assay, Fibroblast Culture
Useful For
Suggests clinical disorders or settings where the test may be helpful
In vitro confirmation of biochemical diagnoses of the following fatty acid oxidation disorders:
-Short-chain acyl-CoA dehydrogenase deficiency
-Medium-chain acyl-CoA dehydrogenase deficiency
-Long-chain 3-hydroxyacyl-CoA dehydrogenase deficiency
-Trifunctional protein deficiency
-Very long-chain acyl-CoA dehydrogenase deficiency
-Carnitine palmitoyl transferase deficiency type II
-Carnitine-acylcarnitine translocase deficiency
Confirmation of the following organic acid disorders:
-2-Methylbutyryl-CoA dehydrogenase deficiency
-Isobutyryl-CoA dehydrogenase deficiency
This test is not useful for prenatal testing.
This assay is not informative if the deficient enzyme is not physiologically expressed in skin fibroblasts.
Additional Tests
Lists tests that are always performed, at an additional charge, with the initial tests.
Test Id | Reporting Name | Available Separately | Always Performed |
---|---|---|---|
CULFB | Fibroblast Culture for Genetic Test | Yes | Yes |
Testing Algorithm
Delineates situations when tests are added to the initial order. This includes reflex and additional tests.
When this test is ordered, fibroblast culture testing will always be performed at an additional charge. If viable cells are not obtained, the client will be notified.
Method Name
A short description of the method used to perform the test
Fibroblasts Incubated with Enriched Medium followed by Tandem Mass Spectrometry (MS/MS)
NY State Available
Indicates the status of NY State approval and if the test is orderable for NY State clients.
Reporting Name
Lists a shorter or abbreviated version of the Published Name for a test
Aliases
Lists additional common names for a test, as an aid in searching
2-Methylbutyrylglycinuria
Trifunctional protein (TFP) deficiency
CACT (Carnitine-Acylcarnitine Translocase) Deficiency
Carnitine Palmitoyl Transferase Deficiency Type II (CPT-II)
Carnitine-Acylcarnitine Translocase (CACT) Deficiency
CPT II (Carnitine Palmitoyl Transferase Deficiency Type II)
IBDH (Isobutyryl-CoA Dehydrogenase) Deficiency
Isobutyryl-CoA Dehydrogenase (IBDH) Deficiency
Isovaleric Acidemia (IVA)
Isovaleryl-CoA Dehydrogenase (IVD) Deficiency
IVA (Isovaleric Acidemia)
IVD (Isovaleryl-CoA Dehydrogenase) Deficiency
LCHAD (Long-Chain 3-Hydroxyacyl-CoA Dehydrogenase) Deficiency
Long-Chain 3-Hydroxyacyl-CoA Dehydrogenase (LCHAD) Deficiency
MCAD (Medium-Chain Acyl-CoA Dehydrogenase) Deficiency
Medium-Chain Acyl-CoA Dehydrogenase (MCAD) Deficiency
SBCAD (Short-Branched Chain Acyl-CoA Dehydrogenase) Deficiency
SCAD (Short-Chain Acyl-CoA Dehydrogenase) Deficiency
Short-Branched Chain Acyl-CoA Dehydrogenase (SBCAD) Deficiency
Short-Chain Acyl-CoA Dehydrogenase (SCAD) Deficiency
TFP (Trifunctional Protein) Deficiency
Very Long-Chain Acyl-CoA Dehydrogenase (VLCAD) Deficiency
VLCAD (Very Long-Chain Acyl-CoA Dehydrogenase) Deficiency
Testing Algorithm
Delineates situations when tests are added to the initial order. This includes reflex and additional tests.
When this test is ordered, fibroblast culture testing will always be performed at an additional charge. If viable cells are not obtained, the client will be notified.
Specimen Type
Describes the specimen type validated for testing
Tissue
Ordering Guidance
This test is recommended only after appropriate analyte testing, including acylcarnitines, organic acids, acylglycines, and/or fatty acids has been performed.
For more information see:
-ACRN / Acylcarnitines, Quantitative, Plasma
-OAU / Organic Acids Screen, Random, Urine
-AGU20 / Acylglycines, Quantitative, Random, Urine
-FAPCP / Fatty Acid Profile, Comprehensive (C8-C26), Serum
Necessary Information
Provide clinical information
Specimen Required
Defines the optimal specimen required to perform the test and the preferred volume to complete testing
Submit only 1 of the following specimens:
Specimen Type: Cultured fibroblasts
Container/Tube: T-75 or T-25 flask
Specimen Volume: 1 Full T-75 flask or 2 full T-25 flasks
Specimen Stability Information: Ambient (preferred)/Refrigerated
Specimen Type: Skin biopsy
Supplies: Fibroblast Biopsy Transport Media (T115)
Container/Tube: Sterile container with any standard cell culture media (eg, minimal essential media, RPMI 1640). The solution should be supplemented with 1% penicillin and streptomycin. Tubes can be supplied upon request (Eagle's minimum essential medium with 1% penicillin and streptomycin).
Specimen Volume: 4-mm punch
Specimen Stability Information: Refrigerated (preferred)/Ambient
Special Instructions
Library of PDFs including pertinent information and forms related to the test
Forms
1. New York Clients-Informed consent is required. Document on the request form or electronic order that a copy is on file. The following documents are available:
-Informed Consent for Genetic Testing (T576)
-Informed Consent for Genetic Testing-Spanish (T826)
2. Biochemical Genetics Patient Information (T602)
3. If not ordering electronically, complete, print, and send a Biochemical Genetics Test Request (T798) with the specimen.
Reject Due To
Identifies specimen types and conditions that may cause the specimen to be rejected
Specimen in formalin or fixative preservative | Reject |
Specimen Stability Information
Provides a description of the temperatures required to transport a specimen to the performing laboratory, alternate acceptable temperatures are also included
Specimen Type | Temperature | Time | Special Container |
---|---|---|---|
Tissue | Varies |
Useful For
Suggests clinical disorders or settings where the test may be helpful
In vitro confirmation of biochemical diagnoses of the following fatty acid oxidation disorders:
-Short-chain acyl-CoA dehydrogenase deficiency
-Medium-chain acyl-CoA dehydrogenase deficiency
-Long-chain 3-hydroxyacyl-CoA dehydrogenase deficiency
-Trifunctional protein deficiency
-Very long-chain acyl-CoA dehydrogenase deficiency
-Carnitine palmitoyl transferase deficiency type II
-Carnitine-acylcarnitine translocase deficiency
Confirmation of the following organic acid disorders:
-2-Methylbutyryl-CoA dehydrogenase deficiency
-Isobutyryl-CoA dehydrogenase deficiency
This test is not useful for prenatal testing.
This assay is not informative if the deficient enzyme is not physiologically expressed in skin fibroblasts.
Testing Algorithm
Delineates situations when tests are added to the initial order. This includes reflex and additional tests.
When this test is ordered, fibroblast culture testing will always be performed at an additional charge. If viable cells are not obtained, the client will be notified.
Clinical Information
Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
Mitochondrial fatty acid beta-oxidation plays an important 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 (acetyl coenzyme A). 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. Disorders of fatty acid oxidation (FAO) are characterized by hypoglycemia, hepatic dysfunction, encephalopathy, skeletal myopathy, and cardiomyopathy. Most FAO disorders have a similar presentation, and their biochemical diagnosis can, at times, be difficult. Commonly used metabolite screens, such as urine organic acids, plasma acylcarnitines, and fatty acids, are influenced by dietary factors and the clinical status of the patient. This can lead to incomplete diagnostic information or even false-negative results. The purpose of the in vitro probe assay is to offer screening for several defects of FAO and organic acid metabolism under controlled laboratory conditions using fibroblast cultures.
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.
An interpretive report will be provided.
Interpretation
Provides information to assist in interpretation of the test results
Abnormal results will include a description of the abnormal profile in comparison to normal and abnormal controls. In addition, the concentration of the acylcarnitine species that abnormally accumulated in the cell medium are provided and compared to the continuously updated reference range based on analysis of normal controls.
Interpretations of abnormal acylcarnitine profiles also include information about the results' significance, a correlation to available clinical information, possible differential diagnoses, recommendations for additional biochemical testing and confirmatory studies if indicated, name and phone number of contacts who may provide these studies, and a phone number to reach one of the laboratory directors in case the referring provider has additional questions.
Cautions
Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
Sometimes, an abnormal acylcarnitine profile cannot differentiate between 2 disorders. In such instances, independent biochemical (eg, specific enzyme assay when available) or molecular genetic analyses are required. Recommendations for such testing will be included in the report.
In addition, electron transfer flavoprotein (ETF) deficiency and ETF-dehydrogenase deficiency (multiple acyl-CoA dehydrogenase deficiency; glutaric acidemia type II) may be, but are not always, detected by this method.
Clinical Reference
Recommendations for in-depth reading of a clinical nature
1. Ensenauer R, Vockley J, Willard JM, et al. A common mutation is associated with a mild, potentially asymptomatic phenotype in patients with isovaleric acidemia diagnosed by newborn screening. Am J Hum Genet. 2004;75(6):1136-1142. doi:10.1086/426318
2. Rinaldo P, Matern D, Bennet MJ. Fatty acid oxidation disorders. Ann Rev Physiol. 2002;64:477-502
3. Shen JJ, Matern D, Millington DS, et al: Acylcarnitines in fibroblasts of patients with long-chain 3-hydroxyacyl-CoA dehydrogenase deficiency and other fatty acid oxidation disorders. J Inherit Metab Dis. 2000;23:27-44. doi:10.1023/a:1005694712583
4. Matern D, Huey JC, Gregersen N, et al. In vitro diagnosis of short-chain acyl-CoA dehydrogenase (SCAD) deficiency. J Inherit Metab Dis. 2001;24(Suppl.1):66
5. Merritt JL, Norris M, Kanungo S. Fatty acid oxidation disorders. Ann. Transl. Med. 2018;6(24):473. doi:10.21037/atm.2018.10.57
Method Description
Describes how the test is performed and provides a method-specific reference
Skin fibroblasts are incubated with cell medium enriched with palmitic acid (C16:0 fatty acid), L-carnitine, and isotopically labeled L-valine ([13]C-Val) and L-isoleucine ([13]C-Ile). Cell lines deficient of one of the enzymes involved in fatty acid oxidation and branched chain amino acid metabolism fail to metabolize acyl-CoA species, which accumulate in the cell medium as acylcarnitines. The medium is separated from the cells following the incubation. The cell pellet is used for protein determination and the medium will be spotted and dried on filter paper. An acylcarnitine analysis is performed by tandem mass spectrometry using a 1/4" filter paper punch, following the addition of isotopically labeled acylcarnitines as internal standards, extraction and derivatization to methyl esters. The assay is performed in triplicate.(Matern D. Acylcarnitines, including in vitro loading tests. In: Blau N, Duran M, Gibson KM, eds. Laboratory Guide to the Methods in Biochemical Genetics. Springer-Verlag; 2008; Cowan T, Pasquali M. Laboratory investigations of inborn errors of metabolism. In: Sarafoglou K, Hoffman GF, Roth KS, eds. Pediatric Endocrinology and Inborn Errors of Metabolism. 2nd ed. McGraw-Hill; 2017:1139-1158)
PDF Report
Indicates whether the report includes an additional document with charts, images or other enriched information
Day(s) Performed
Outlines the days the test is performed. This field reflects the day that the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time before the test is performed. Some tests are listed as continuously performed, which means that assays are performed multiple times during the day.
Varies
Report Available
The interval of time (receipt of sample at Mayo Clinic Laboratories to results available) taking into account standard setup days and weekends. The first day is the time that it typically takes for a result to be available. The last day is the time it might take, accounting for any necessary repeated testing.
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
Indicates the location of the laboratory that performs the test
Fees :
Several factors determine the fee charged to perform a test. Contact your U.S. or International Regional Manager for information about establishing a fee schedule or to learn more about resources to optimize test selection.
- Authorized users can sign in to Test Prices for detailed fee information.
- Clients without access to Test Prices can contact Customer Service 24 hours a day, seven days a week.
- Prospective clients should contact their account representative. For assistance, contact Customer Service.
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 instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR) product.
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
Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Clinic Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.
CPT codes are provided by the performing laboratory.
CPT codes are provided by the performing laboratory.
82017
LOINC® Information
Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the order and results codes of this test. LOINC values are provided by the performing laboratory.
Test Id | Test Order Name | Order LOINC Value |
---|---|---|
FAO | Fatty Acid Ox Probe Assay, Fibro | 74533-1 |
Result Id | Test Result Name |
Result LOINC Value
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
|
---|---|---|
23487 | Interpretation | 59462-2 |
23489 | Reviewed By | 18771-6 |