Test Catalog

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 (SCAD) 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 deficiency type II (CPT-II)

-Carnitine-acylcarnitine translocase (CACT) deficiency

 

Confirmation of the following organic acid disorders:

-2-Methylbutyryl-CoA dehydrogenase (SBCAD) deficiency

-Isobutyryl-CoA dehydrogenase (IBD) deficiency

 

This test is not useful for prenatal testing.

 

This assay is not informative if the deficient enzyme is physiologically not 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
FIBR Fibroblast Culture Yes Yes
CRYOB Cryopreserve for Biochem Studies No Yes

Testing Algorithm
Delineates situations when tests are added to the initial order. This includes reflex and additional tests.

When this test is ordered, a fibroblast culture and cryopreservation for biochemical studies will always be performed at an additional charge. However, for multiple assays on a patient utilizing fibroblast culture, only one culture is required regardless of the number of assays ordered. If viable cells are not obtained within 30 days, client will be notified.

 

See Newborn Screening Follow-up for Isolated C5 Acylcarnitines Elevations (also applies to any plasma or serum C5 acylcarnitine elevations) in Special Instructions.

Special Instructions
Library of PDFs including pertinent information and forms related to the test

Method Name
A short description of the method used to perform the test

FAO: Fibroblasts Incubated with Enriched Medium followed by Tandem Mass Spectrometry (MS/MS)

CRYOB: Fibroblast Subculture followed by Cryopreservation and Storage

NY State Available
Indicates the status of NY State approval and if the test is orderable for NY State clients.

Yes

Reporting Name
Lists a shorter or abbreviated version of the Published Name for a test

Fatty Acid Ox Probe Assay, Fibro

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, a fibroblast culture and cryopreservation for biochemical studies will always be performed at an additional charge. However, for multiple assays on a patient utilizing fibroblast culture, only one culture is required regardless of the number of assays ordered. If viable cells are not obtained within 30 days, client will be notified.

 

See Newborn Screening Follow-up for Isolated C5 Acylcarnitines Elevations (also applies to any plasma or serum C5 acylcarnitine elevations) in Special Instructions.

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; and 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 24 hours

 

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 in Special Instructions:

-Informed Consent for Genetic Testing (T576)

-Informed Consent for Genetic Testing-Spanish (T826)

2. Biochemical Genetics Patient Information (T602) in Special Instructions.

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 (preferred)

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 (SCAD) 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 deficiency type II (CPT-II)

-Carnitine-acylcarnitine translocase (CACT) deficiency

 

Confirmation of the following organic acid disorders:

-2-Methylbutyryl-CoA dehydrogenase (SBCAD) deficiency

-Isobutyryl-CoA dehydrogenase (IBD) deficiency

 

This test is not useful for prenatal testing.

 

This assay is not informative if the deficient enzyme is physiologically not 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, a fibroblast culture and cryopreservation for biochemical studies will always be performed at an additional charge. However, for multiple assays on a patient utilizing fibroblast culture, only one culture is required regardless of the number of assays ordered. If viable cells are not obtained within 30 days, client will be notified.

 

See Newborn Screening Follow-up for Isolated C5 Acylcarnitines Elevations (also applies to any plasma or serum C5 acylcarnitine elevations) in Special Instructions.

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. 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 those 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.

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 Dec;6(24):473. doi: 10.21037/atm.2018.10.57

Special Instructions
Library of PDFs including pertinent information and forms related to the test

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 (MS/MS) 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, incl. 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

No

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.

15 to 71 days depending on rapidity of growth

Specimen Retention Time
Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded

3 years-Check with the lab for availability

Performing Laboratory Location
Indicates the location of the laboratory that performs the test

Rochester

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 Regional Manager. 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. This test 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.

82017-Acylcarnitines; quantitative, each specimen

88233-Fibroblast culture

88240-Cryopreservation for biochemical studies

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 35574-3
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

Test Setup Resources

Setup Files
Test setup information contains test file definition details to support order and result interfacing between Mayo Clinic Laboratories and your Laboratory Information System.

Excel | Pdf

Sample Reports
Normal and Abnormal sample reports are provided as references for report appearance.

Normal Reports | Abnormal Reports

SI Sample Reports
International System (SI) of Unit reports are provided for a limited number of tests. These reports are intended for international account use and are only available through MayoLINK accounts that have been defined to receive them.

SI Normal Reports | SI Abnormal Reports