A second-order screening test for the presumptive diagnosis of pheochromocytoma in patients with nonepisodic hypertension
Confirming positive plasma metanephrine results in patients with nonepisodic hypertension
Specimen Type
Random Urine
Specimen Requirements
Urine Cup
Specimen Collection / Processing Instructions
Patient Preparation: Tricyclic antidepressants and labetalol and sotalol (beta blockers) may elevate levels of metanephrines. If clinically feasible, these medications should be discontinued at least 1 week before collection
All specimens will be evaluated at Mayo Clinic Laboratories for test suitability
Limitations
This test utilizes a liquid chromatography tandem mass spectrometry (LC-MS/MS) 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 also not subject to the known interference of acetaminophen (seen with the plasma metanephrine HPLC-EC method)
When N-acetylcysteine is administered at levels sufficient to act as an antidote for the treatment of acetaminophen overdose, it may lead to falsely decreased creatinine results.
