| A B C D E F G H I J K L M N O P Q R S T U V W X Y Z # |
Carnitine, Serum
Test CodeCARNT
Alias/See Also
Epic: LAB6885
Mayo: CARNS
Mayo: CARNS
CPT Codes
82379
Preferred Specimen
Specimen Type: Serum
Collection Container: Serum gel
Specimen Volume: 0.5 mL
Minimum Volume
0.2 mL
Other Acceptable Specimens
Collection Container: Red top
Instructions
Centrifuge and aliquot serum into a plastic vial.
Transport Container
Plastic vial
Specimen Stability
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Serum | Frozen (preferred) | 60 days | |
| Refrigerated | 21 days | ||
| Ambient | 7 days |
Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
REJECT DUE TO
| Gross hemolysis | OK |
| Gross lipemia | OK |
| Gross icterus | OK |
Methodology
Flow Injection Analysis-Tandem Mass Spectrometry (FIA-MS/MS)
Setup Schedule
Monday through Friday
Report Available
2 to 5 days
Reference Range
| Total carnitine (TC) | Free carnitine (FC) | Acylcarnitine (AC) | AC/FC Ratio | |
| Age Group | Range* | Range* | Range* | Range |
| < or =1 day | 23-68 | 12-36 | 7-37 | 0.4-1.7 |
| 2-7 days | 17-41 | 10-21 | 3-24 | 0.2-1.4 |
| 8-31 days | 19-59 | 12-46 | 4-15 | 0.1-0.7 |
| 32 days-12 months | 38-68 | 27-49 | 7-19 | 0.2-0.5 |
| 13 months-6 years | 35-84 | 24-63 | 4-28 | 0.1-0.8 |
| 7-10 years | 28-83 | 22-66 | 3-32 | 0.1-0.9 |
| 11-17 years | 34-77 | 22-65 | 4-29 | 0.1-0.9 |
| > or =18 years | 34-78 | 25-54 | 5-30 | 0.1-0.8 |
Schmidt-Sommerfeld E, Werner E, Penn D: Carnitine plasma concentrations in 353 metabolically healthy children. Eur J Pediatr. 1988;147:356-360
Used with permission of European Journal of Pediatrics.
Clinical Significance
USEFUL FOR
Evaluation of patients with a clinical suspicion of a wide range of conditions including organic acidemias, fatty acid oxidation disorders, and primary carnitine deficiency using serum specimens
CLINICAL INFORMATION
Carnitine and its esters are required for normal energy metabolism and serve 4 primary functions:
-Importing long-chain fatty acids into the mitochondria
-Exporting naturally-occurring short-chain acyl-CoA groups from the mitochondria
-Maintaining the ratio of free CoA to esterified CoA
-Removing potentially toxic acyl-CoA groups from the cells and tissues
Evaluation of carnitine in serum, plasma, and urine is a biochemical screening test for suspected primary disorders of the carnitine cycle or secondary disturbances in carnitine levels as a result of organic acidemias and fatty acid oxidation disorders. In the latter disorders, acyl-CoA groups accumulate and are excreted into the urine and bile as carnitine derivatives, resulting in a secondary carnitine deficiency. More than 100 such primary and secondary disorders have been described. Collectively, their incidence is approximately 1 in 1000 live births. Primary carnitine deficiency has an incidence of approximately 1 in 21,000 live births based on Minnesota newborn screening data.
Other conditions that could cause an abnormal carnitine level include neuromuscular diseases, gastrointestinal disorders, familial cardiomyopathy, renal tubulopathies and chronic renal failure (dialysis), and prolonged treatment with steroids, antibiotics (pivalic acid), anticonvulsants (valproic acid), and total parenteral nutrition.
Follow-up testing is required to differentiate primary and secondary carnitine deficiencies and to elucidate the exact cause.
Evaluation of patients with a clinical suspicion of a wide range of conditions including organic acidemias, fatty acid oxidation disorders, and primary carnitine deficiency using serum specimens
CLINICAL INFORMATION
Carnitine and its esters are required for normal energy metabolism and serve 4 primary functions:
-Importing long-chain fatty acids into the mitochondria
-Exporting naturally-occurring short-chain acyl-CoA groups from the mitochondria
-Maintaining the ratio of free CoA to esterified CoA
-Removing potentially toxic acyl-CoA groups from the cells and tissues
Evaluation of carnitine in serum, plasma, and urine is a biochemical screening test for suspected primary disorders of the carnitine cycle or secondary disturbances in carnitine levels as a result of organic acidemias and fatty acid oxidation disorders. In the latter disorders, acyl-CoA groups accumulate and are excreted into the urine and bile as carnitine derivatives, resulting in a secondary carnitine deficiency. More than 100 such primary and secondary disorders have been described. Collectively, their incidence is approximately 1 in 1000 live births. Primary carnitine deficiency has an incidence of approximately 1 in 21,000 live births based on Minnesota newborn screening data.
Other conditions that could cause an abnormal carnitine level include neuromuscular diseases, gastrointestinal disorders, familial cardiomyopathy, renal tubulopathies and chronic renal failure (dialysis), and prolonged treatment with steroids, antibiotics (pivalic acid), anticonvulsants (valproic acid), and total parenteral nutrition.
Follow-up testing is required to differentiate primary and secondary carnitine deficiencies and to elucidate the exact cause.
Performing Laboratory
Mayo Clinic Laboratories - Rochester
3050 Superior Drive NW
Rochester, MN 55901
Last Updated: June 12, 2023
Last Review: N. Wolford, June 12, 2023