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Test Code C4U C4 Acylcarnitine, Quantitative, Urine

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Useful For

Evaluation of patients with abnormal newborn screens showing elevations of iso-/butyrylcarnitine (C4) to aid in the differential diagnosis of short-chain acyl-CoA dehydrogenase and isobutyryl-CoA dehydrogenase deficiencies

Method Name

Flow Injection Analysis-Tandem Mass Spectrometry (FIA-MS/MS)


Necessary Information


Include patient's age, family history, clinical condition (asymptomatic or acute episode), diet, and drug therapy information.

Specimen Required


Patient Preparation: If clinically feasible, discontinue L-carnitine supplementation at least 72 hours before specimen collection.

Supplies: Urine Tubes, 10 mL (T068)

Collection Container/Tube: Clean, plastic urine collection container

Submission Container/Tube: Plastic, 10 mL urine tube

Specimen Volume: 5 mL

Collection Instructions:

1. Collect a random urine specimen.

2. Freeze specimen immediately.


Reporting Name

C4 Acylcarnitine, QN, U

Specimen Type

Urine

Specimen Minimum Volume

1 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Urine Frozen (preferred) 7 days
  Refrigerated  24 hours

Reject Due To

All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.

Reference Values

<3.00 millimoles/mole creatinine

Day(s) and Time(s) Performed

Monday, Wednesday, Friday; 8 a.m.

Test Classification

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 U.S. Food and Drug Administration.

CPT Code Information

82017

LOINC Code Information

Test ID Test Order Name Order LOINC Value
C4U C4 Acylcarnitine, QN, U 53111-1

 

Result ID Test Result Name Result LOINC Value
88829 C4 Acylcarnitine, QN, U 53111-1
28075 C4 Interpretation 59462-2
34468 Reviewed By 18771-6

Forms

If not ordering electronically, complete, print, and send an Inborn Errors of Metabolism Test Request (T798) with the specimen. 

Testing Algorithm

See Newborn Screening Follow-up for Isolated C4 Acylcarnitine Elevations (also applies to any plasma or serum C4 acylcarnitine elevation) in Special Instructions.