Test Code C5OHU C5-OH Acylcarnitine, Quantitative, Urine
Reporting Name
C5-OH Acylcarnitine, QN, UUseful For
Evaluation of patients with an abnormal newborn screen showing elevations of 3-hydroxyisovaleryl-/2-methyl-3-hydroxybutyryl-carnitine (C5-OH)
Performing Laboratory

Specimen Type
UrineNecessary 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
<2.93 millimoles/mole creatinine
Day(s) and Time(s) Performed
Monday, Wednesday, Friday
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 |
---|---|---|
C5OHU | C5-OH Acylcarnitine, QN, U | 50091-8 |
Result ID | Test Result Name | Result LOINC Value |
---|---|---|
88830 | C5-OH Acylcarnitine, QN, U | 50091-8 |
28125 | C5-OH Interpretation | 59462-2 |
34469 | Reviewed By | 18771-6 |
Clinical Information
The differential diagnosis of an isolated elevation of 3-hydroxyisovaleryl-/2-methyl-3-hydroxy acylcarnitine (C5-OH) in plasma or (newborn screening) blood spots includes the following disorders:
-3-Methylcrotonyl-CoA carboxylase deficiency (common name: 3-methylcrotonylglycinuria), either infantile or maternal
-3-Hydroxy 3-methylglutaryl-(HMG)-CoA lyase deficiency
-Beta-ketothiolase deficiency
-2-Methyl 3-hydroxybutyryl-CoA dehydrogenase deficiency
-3-methylglutaconic aciduria type I
-Biotinidase deficiency
-Holocarboxylase deficiency
Confirmatory and diagnostic testing are necessary to differentiate these clinical entities. This test can be used to differentiate patients with 3-methylcrotonylglycinuria and with 3-methylglutaconic aciduria as they typically excrete larger amounts of C5-OH in urine compared to patients with the other diagnoses.
The American College of Medical Genetics (ACMG) newborn screening work group published diagnostic algorithms for the follow-up of infants who had positive newborn screening results. For more information, see the Practice Resources: ACT Sheets and Algorithms at http://www.acmg.net.
Analytic Time
2 days (not reported on Sunday)Reject Due To
All specimens will be evaluated at Mayo Clinic Laboratories for test suitability. |
NY State Approved
YesMethod Name
Flow Injection Analysis-Tandem Mass Spectrometry (FIA-MS/MS)
Forms
If not ordering electronically, complete, print, and send an Inborn Errors of Metabolism Test Request (T798) with the specimen.