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|80535:CATECHOLAMINES FRACTIONATED, FREE, URINE|
|Methodology:||Tandem Mass Spectrometry (MS/MS)|
|Released:||24-48 hours after setup at PeaceHealth Laboratories’ reference lab.|
|Specimen Collection Details|
|Collection:||24-hour or random urine. Refrigerate 24-hour specimen during collection, storage and transport. NOTE: Patient to abstain from mediation for 72 hours prior to collection.|
|Handling:||5 mL aliquot from a well mixed 24-hour or random collection. Record total volume. Refrigerate.|
|Stability:||24 hours ambient, 30 days refrigerated, or 6 months frozen. Adequate refrigeration is the most important aspect of specimen preservation and can be enhanced by adjusting the pH to 2.0-3.0 by adding an acid, such as 6N HCl. Catecholamines are not stable above pH 7.0. The pH of such specimens must be adjusted by the addition of acid prior to transport. A pH less than 2.0 can cause assay interference.|
|Standard Volume:||5 mL urine.|
|Minimum Volume:||250 µL urine.|
|Comments:||Secreting neuroendocrine tumors are typically associated with catecholamine concentrations several times higher than the upper reference intervals. Large elevations can be seen in live-threatening illnesses and drug interferences. Common reasons for slight and moderate elevations include intense physical activity, emotional and physical stress, drug interferences, and improper specimen collection.
Medications which may physiologically interfere with catecholamines and metabolites include amphetamines and amphetamine-like compounds, appetite suppressants, bromocriptine, buspirone, caffeine, carbidopa-levodopa (Sinemet), clonidine, dexamethasone, diuretics (in doses sufficient to deplete sodium), ethanol, isoproterenol, methyldopa (Aldomet), MAO inhibitors, nicotine, nose drops, propafenone (Rythmol), reserpine, theophylline, tricyclic antidepressants, and vasodilators. The effects of some drugs on catecholamine results may not be predictable.
The urine catecholamines-to-creatinine ratios will be reported when the patient is under 18 years, or the urine collection is random, or other than 24 hours, or the urine volume is less than 400 mL/24 hours.