Sign in →

Test ID C4U C4 Acylcarnitine, Quantitative, Random, Urine

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

Genetics Test Information

This test is used to differentiate the potential diagnoses of short chain acyl-CoA dehydrogenase (SCAD) versus isobutyryl-CoA dehydrogenase deficiency.

Highlights

Elevated iso-/butyrylcarnitine (C4) in plasma or newborn screening blood spots is due to either short chain acyl-CoA dehydrogenase (SCAD) deficiency or isobutyryl-CoA dehydrogenase (IBD) deficiency.

 

Urine C4 results can distinguish between SCAD deficiency, which results in normal C4 in urine, and IBD deficiency, which results in elevated C4 in urine.

Method Name

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

Reporting Name

C4 Acylcarnitine, QN, U

Specimen Type

Urine


Ordering Guidance


This second-tier test is used specifically to evaluate a newborn screening elevation of iso-/butyrylcarnitine (C4) and must not be ordered with either C5OHU / C5-OH Acylcarnitine, Quantitative, Random, Urine or C5DCU / C5-DC Acylcarnitine, Quantitative, Random, Urine.

 

For general screening for metabolic disorders, see OAU / Organic Acids Screen, Random, Urine; ACRN / Acylcarnitines, Quantitative, Plasma; and AAQP / Amino Acids, Quantitative, Plasma.



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.


Specimen Minimum Volume

1 mL

Specimen Stability Information

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

Reference Values

<3.00 millimoles/mole creatinine

Day(s) Performed

Monday, Wednesday, Friday

Performing Laboratory

Mayo Clinic Laboratories in Rochester

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

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 US Food and Drug Administration.

Report Available

2 to 5 days

NY State Approved

Yes

Forms

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