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Test Code Acylcarn Acylcarnitine

Clinical System Name

Acylcarnitine Profile, Blood



Acylcarnitine Blood


Measurement of acylcarnitines by ESI-MS/MS using stable isotope internal standards. Free carnitine is also reported. An order for "Free/Total Carnitine" in addition to "Acylcarnitine" would be considered a duplicate.


Free carnitine is included within the report; simultaneous order for free/total carnitine will be considered a duplicate and cancelled.



Sample Requirements

Specimen: Whole Blood

Container(s): Dark Green/Sodium Heparin, Lt. Green/ Lithium Heparin

Preferred Vol: 1.0 mL

Minimum Vol: 0.5 mL


Note:   Serum is also acceptable. Test can be done on dried blood spots (3 full spots on a newborn screening card), however, plasma is the preferred sample type, especially for follow up testing of an abnormal newborn screen.

Processing Instructions

Reject due to:

Spin: Y

Aliquot: Y

Temp: -20 C

Storage location: CPA Freezer, Biochemical Genetics Box


Off-site collection: Freeze and ship heparinized plasma or serum (preferred sample type).  Blood spotted on newborn screening filter card should be shipped at room temperature.


Temperature Time
Room temp 5 days
Refrigerated 5 days
Frozen (-200C) (serum/plasma) 1 month



STAT Performed TAT
N T, Th 3-7 days


Contact the Biochemical Genetics Lab for requests outside of stated availability (206)987-2216.

Performing Laboratory

Seattle Children's Laboratory    


Department:  Biochemical Genetics

Phone Number: 206-987-2216




Method: Tandem mass spectrometry

Analytical Volume: 0.2 mL


CPT Codes



Biochemical Genetics Requisition


On the requisition include clinical information needed for appropriate interpretation.  (Age, gender, drug therapy, and family history)

Clinical Utility

Analysis of acylcarnitines is useful in diagnosis of defects in fatty acid beta-oxidation and various disorders of organic acid metabolism. Acylcarnitine analysis is often used in conjunction with urine organic acid analysis in the diagnosis of these disorders and in followup of presumptive positive newborn screening results.