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Metanephrines, Fractionated, Urine, 24-Hour
MessageSendout, Mayo test code: METAF
Test Code
LAB409
Alias/See Also
Free Metanephrine
Metanephrines free, urine
NMN (Normetanephrines), urine
Normetanephrine, (NMN), free
Normetanephrines, urine
Fractionated metanephrines
METAF
Metanephrines free, urine
NMN (Normetanephrines), urine
Normetanephrine, (NMN), free
Normetanephrines, urine
Fractionated metanephrines
METAF
CPT Codes
83535
Preferred Specimen
10 mL from a 24-hour urine collected in 25 mL (pediatric: 15 mL) of 50% acetic acid as preservative at start of collection.
Patient Preparation
Tricyclic antidepressants, labetalol, and sotalol medications may elevate levels of metanephrines producing results that cannot be interpreted. If clinically feasible, it is optimal to discontinue these medications at least 1 week before collection. For advice on assessing the risk of removing patients from these medications and alternatives, consider consultation with a specialist in endocrinology or hypertension.
Minimum Volume
3 mL
Other Acceptable Specimens
URINE PRESERVATIVE COLLECTION OPTIONS
Note: The addition of preservative must occur prior to the start of the collection or application of temperature controls must occur during collection.
| Ambient | No |
| Refrigerate | OK |
| Frozen | OK |
| 50% Acetic Acid | Preferred |
| Boric Acid | Preferred |
| Diazolidinyl Urea | No |
| 6M Hydrochloric Acid | OK |
| 6M Nitric Acid | OK |
| Sodium Carbonate | OK |
| Thymol | No |
| Toluene | OK |
Instructions
1. Collect urine for 24 hours.
2. Add 10 g (pediatric: 3 g) of boric acid or 25 mL (pediatric: 15 mL) of 50% acetic acid as preservative at start of collection.
2. Add 10 g (pediatric: 3 g) of boric acid or 25 mL (pediatric: 15 mL) of 50% acetic acid as preservative at start of collection.
Transport Container
Plastic urine tube
Transport Temperature
Refrigerated
Specimen Stability
Refrigerated (preferred): 28 days
Frozen: 28 days
Ambient: 28 days
Frozen: 28 days
Ambient: 28 days
Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.
Methodology
Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS) Stable Isotope Dilution Analysis
FDA Status
Approved
Setup Schedule
Monday through Friday
Report Available
3-5 days
Limitations
This test utilizes a liquid chromatography/tandem mass spectrometry method and is not affected by the interfering substances that affected the previously utilized spectrophotometric (Pisano reaction) method (ie, diatrizoate, chlorpromazine, hydrazine derivatives, imipramine, monamine oxidase [MAO] inhibitors, methyldopa, phenacetin, ephedrine, or epinephrine).
This method is not subject to the known interference of acetaminophen (seen with the plasma metanephrine high performance liquid chromatography-electrochemical method).
This method is not subject to the known interference of acetaminophen (seen with the plasma metanephrine high performance liquid chromatography-electrochemical method).
Reference Range
Included with report
Clinical Significance
A first- and second-order screening test for the presumptive diagnosis of catecholamine-secreting pheochromocytomas and paragangliomas
Confirming positive plasma metanephrine results
Confirming positive plasma metanephrine results
Performing Laboratory
Mayo Clinic Laboratories, Rochester, Minnesota
Additional Information
Metanephrines, Fractionated, 24 Hour, Urine
