Metanephrines Fractionated Free, Plasma

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Test Codes

EPIC: LAB1232462, Beaker: METS FRACT P, Quest: 19548

Department

Send Outs

Instructions

• Patients should be relaxed in either a supine or upright position before blood is drawn.

• Patient should avoid alcohol, coffee, tea, tobacco and strenuous exercise prior to collection. Overnight fasting is preferred.

Specimen Collection Criteria

Collect (preferred): Draw specimen in one prechilled Pink-top (K₂EDTA) tube.

Also Acceptable: Draw specimen in one prechilled Lavender-top (EDTA) tube.

The whole blood sample should be kept on wet ice until centrifuged (preferably at 4°C) to separate the plasma within 2 hours of venipuncture. After centrifugation, the plasma should be transferred to a transport tube and immediately refrigerated.

Physician Office/Draw Specimen Preparation

Centrifuge to separate plasma from cells within 2 hours of collection. Transfer plasma to plastic transport tube and refrigerate at (2-8°C or 36-46) prior to transport.

Preparation for Courier Transport

Transport: 2.5 mL plasma, refrigerated at (2-8°C or 36-46). (Minimum: 1.5 mL)

Rejection Criteria

• Heparinized plasma.
• Serum.
• CSD.
• Urine.
• Specimens not collected and processed as indicated.

Inpatient Specimen Preparation

Transport specimens to the Laboratory immediately on wet ice, after collection.

In-Lab Processing

Centrifuge to separate plasma from cells within 2 hours of collection. Transfer plasma to plastic transport tube and refrigerate (2-8°C or 36-46) prior to transport.

Transport: 2.5 mL plasma, refrigerated (2-8°C or 36-46). (Minimum: 1.5 mL)

Storage

Specimen Stability for Testing:

Room Temperature (20-26°C or 68-78.8°F): 24 hours
Refrigerated (2-8°C or 36-46°F): 14 days
Frozen (-20°C/-4°F or below): 30 days

Specimen Storage in Department Prior to Disposal:

Specimen retention time is determined by the policy of the reference laboratory. Contact the Send Outs Laboratory with any questions.

Laboratory

Sent to Quest Diagnostics, Wood Dale, IL.

Performed

Monday – Saturday.
Results available in 5-6 days.

Reference Range

Metanephrine, Free	≤57 pg/mL
Normetanephrine, Free	≤148 pg/mL
Total, Free (MN + NMN)	≤205 pg/mL

Test Methodology

Chromatography / Mass Spectrometry

Clinical Utility

Metanephrines, Fractionated, Free, LC/MS/MS, Plasma – Normetanephrine (NM) and Metanephrine (MN) are the extra- neuronal Catechol-O-Methyl Transferase (COMT) metabolites of the catecholamines norepinephrine and epinephrine, respectively. Measurement of plasma metanephrines is more sensitive (but may be less specific) than measurement of catecholamines for the detection of pheochromocytoma. Proper interpretation of results requires awareness of recent medication/drug history (e.g., antihypertensive agents, alcohol, cocaine) and other pre-analytical factors (e.g., stress, severe congestive heart failure, myocardial infarction) that influence release of catecholamines and metanephrines.

CPT Codes

83835

Contacts

Last Updated

10/6/2026