ARUP's Laboratory Test Directory
| 0050184: Metanephrines, Plasma (Free) |
| Test Mnemonic: META PF | |
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Methodology: High Performance Liquid Chromatography
Performed: Sun, Tue-Sat Reported: 2-6 days |
| Specimen Required: | |
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Collect: One 7 mL lavender (EDTA) or pink (K2EDTA).
Transport: 4 mL plasma, frozen. (Min: 1.5 mL) Submit specimen in an ARUP Standard Transport Tube. Pediatric Collection/Transport: 1.5 mL plasma, frozen. Remarks: CRITICAL FROZEN. Separate specimens must be submitted when multiple tests are ordered. Remove plasma from cells and freeze ASAP. Patient Preparation: Discontinue epinephrine and epinephrine-like drugs at least one 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 four hours before the specimen is drawn. Collect the sample after the patient has had 15 minutes rest in a supine position. An overnight fast prior to sample collection is recommended. Unacceptable Conditions: Grossly hemolyzed, ambient, or refrigerated specimens. Sodium citrate-preserved plasma. Stability: After separation from cells: Ambient: Unacceptable; Refrigerated: Unacceptable; Frozen: 1 month |
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| Reference Interval: |
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Normetanephrine: 0.0-0.89 nmol/L Metanephrine: 0.0-0.49 nmol/L |
| Interpretive Data: | |
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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.
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| CPT Code(s): | |
| 83835 |