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|92315:METANEPHRINES, PLASMA (FREE)|
|Alias Names:||Metanephrine, Plasma / Metanephrines, Fractionated Plasma / Normetanephrine, Plasma / Quantitative Metanephrines|
|Methodology:||High Performance Liquid Chromatography (HPLC)|
|Released:||2-6 days after setup at PeaceHealth Laboratories’ reference lab.|
|Specimen Collection Details|
|Collection:||NOTE: Discontinue epinephrine and epinephrine-like drugs at least 1 week before obtaining the specimen. The patient must refrain from using acetaminophen for 48 hours before the specimen is drawn. The patient must refrain from using caffeine, medications, and tobacco and from drinking coffee, tea, or alcoholic beverages for at least 4 hours before the specimen is drawn. Collect the specimen after the patient has had 15 minutes in a supine position. An overnight fast before collection is recommended.
Two 4 mL lavender top tubes (EDTA) or two 6 mL pink top tubes (EDTA K2). Immediately place in wet ice bath.
|Handling:||Centrifuge at 4° C within 1 hour of collection. Remove plasma into a plastic vial and freeze immediately. Critical frozen.|
|Stability:||1 month frozen. Unstable ambient or refrigerated.|
|Standard Volume:||4 mL plasma.|
|Minimum Volume:||1.5 mL plasma.|
|Transport:||Frozen, on dry ice.|
|Rejection Criteria:||Gross hemolysis; ambient or refrigerated specimen; sodium citrate preserved plasma.|
|Patients with essential hypertension and plasma concentrations of normetanephrine and metanephrine below 0.9 nmol/L and 0.5 nmol/L, respectively, can be reliably excluded from further testing for the detection of a pheochromocytoma. The majority of patients with pheochromocytoma have a plasma normetanephrine concentration in excess of 2.2 nmol/L and/or metanephrine concentrations in excess of 1.1 nmol/L. The presence of increased concentrations of the analytes serves as confirmation for the diagnosis of the tumor.|