Acylcarnitine Analysis — Basic (Test 2000)

CPT Code(s): 82017

Ordering Recommendation: This test is intended to be used in the diagnosis and clinical management of patients with inborn errors of metabolism related to fatty acid oxidation and/or organic acidemias.

Synonyms: Acylcarnitine profiling analysis, ACP

Methodology: Flow injection analysis tandem mass spectrometry (FIA-MS/MS) of butyl esters.

Performed: Multiple times per week, Monday through Friday

Reported: 7 days or less

Patient Preparation: None required

Specimen Type: frozen plasma/serum

Collection Tube (preferred): sodium heparin (green top)

Collection Tube (other acceptable): lithium heparin (green top), serum (red top)

Processing: Separate plasma/serum from whole blood and transfer to a plastic transport tube and freeze as soon as possible. If multiple different tests are ordered, submitting separate frozen aliquots for each may improve TAT.

Specimen Volume: 0.5 ml (minimum of 0.1 ml)

Storage: Must be stored at -20°C.   

Shipment: Ship samples frozen on 3-5 lbs. of dry ice in an insulated container using overnight courier.   

Unacceptable Conditions:

• Specimen requirements listed above not met.
• Sample fully thawed during shipment.
• Sample has excessive hemolysis or clotting.
• Sample collected in gel tube (plasma separator tube (PST) or serum separator tube (SST)).

Stability: 90 days in the freezer (-20°C)

Reference Interval: by report

Interpretation: A brief interpretation of results is provided with each test.

Limitations:

False negative results can occur in rare situations when diet, treatment or secondary carnitine depletion causes acylcarnitine levels to appear normal in an affected individual. In addition, in rare situations, false positive results can arise due to interference from competing isobaric compounds. Values are most informative when compared to the provided laboratory specific normal range.

This method does not quantify free carnitine or resolve isobaric acylcarnitine species. Additional testing of free and total carnitine (TEST 5000) and urine organic acid analysis (TEST 3000) is sometimes needed to clarify findings.

Results should be interpreted in the context of clinical symptoms and concurrent testing. In the case of a new diagnosis, acylcarnitine results should be confirmed with additional biochemical or molecular genetic testing.

This test was developed and its performance characteristics determined by Indiana University Biochemical Genetics Laboratory. It has not been cleared or approved by the U.S. Food and Drug Administration. This test is used for clinical purposes. It should not be regarded as investigational or for research. The laboratory is certified under the Clinical Laboratory Improvement Amendments of 1988 (CLIA ’88) as qualified to perform high complexity clinical laboratory testing. CLIA# 15D0647198, CAP# 1678930

Reference:

• Scott, D., Heese, B., Uttam, G., Quantification of Free Carnitine and Acylcarnitines in Plasma or Serum Using UPLC/MS/MS (2016), Clinical Applications of Mass Spectrometry in Biomolecular Analysis: Methods and Protocols., Methods in Molecular Biology, vol 1378.
• Rinaldo, P., Cowan, T.M., Mattern, D., ACMG Standards and Guidelines: Acylcarnitine profile analysis, (2008), Genetics in Medicine, Vol 10, No 2.