Isobutyryl/butyryl-carnitine (C4) Quantitative, Urine
Also known as: C4 URINE
Use
This test aids in the differential diagnosis of short-chain acyl-CoA dehydrogenase (SCAD) and isobutyryl-CoA dehydrogenase (IBD) deficiencies. It is recommended for follow-up when an abnormal newborn screening or plasma acylcarnitine profile indicates an isolated elevation of C4-carnitine. It should be used in conjunction with other tests such as Acylcarnitine Quantitative Profile, Plasma, Organic Acids, Urine, and Acylglycines, Quantitative, Urine.
Special Instructions
If the patient is receiving carnitine supplements, the test results may not be informative. A complete clinical history including age, gender, diet, drug therapy, and family history is necessary for accurate interpretation. A Biochemical Genetics Patient History Form should be completed to facilitate the process.
Limitations
The test has not been cleared or approved by the U.S. Food and Drug Administration and was developed and its performance characteristics determined by ARUP Laboratories. Clinical correlation is recommended for interpretation of the result, especially if the patient is receiving carnitine supplements. Specimens that have undergone more than three freeze/thaw cycles are not acceptable.
New York Approved
Methodology
Mass Spectrometry
Biomarkers
LOINC Codes
- 2161-8
- 53111-1
Result Turnaround Time
4-11 days
Related Documents
For more information, please review the documents below
Specimen
Urine
Volume
2.5 mL
Minimum Volume
1.0 mL
Container
ARUP standard transport tube
Collection Instructions
Random urine. Transfer to tube and freeze immediately.
Storage Instructions
Frozen. Separate specimens for multiple tests.
Causes for Rejection
Specimens exposed to more than three freeze/thaw cycles.
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | Unacceptable |
| Refrigerated | 1 week |
| Frozen | 1 month |