Test Catalog

Test Id : METRN

Metanephrines, Fractionated, Random, Urine

Useful For
Suggests clinical disorders or settings where the test may be helpful

A second-order screening test for the presumptive diagnosis of pheochromocytoma in patients with non-episodic hypertension


Confirming positive plasma metanephrine results in patients with non-episodic hypertension

Profile Information
A profile is a group of laboratory tests that are ordered and performed together under a single Mayo Test ID. Profile information lists the test performed, inclusive of the test fee, when a profile is ordered and includes reporting names and individual availability.

Test Id Reporting Name Available Separately Always Performed
METAU Metanephrines, Fractionated, U No Yes
CRETR Creatinine, Random, U Yes, (Order RCTUR) Yes

Method Name
A short description of the method used to perform the test

METAU: Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS) Stable Isotope Dilution Analysis

CRETR: Enzymatic Colorimetric Assay

NY State Available
Indicates the status of NY State approval and if the test is orderable for NY State clients.


Reporting Name
Lists a shorter or abbreviated version of the Published Name for a test

Metanephrines, Fract., Random, U

Lists additional common names for a test, as an aid in searching

Fractionated metanephrines

Metanephrines free, urine

NMN (Normetanephrines), urine

Normetanephrine, (NMN), free

Normetanephrines, urine




Specimen Type
Describes the specimen type validated for testing


Specimen Required
Defines the optimal specimen required to perform the test and the preferred volume to complete testing

Patient Preparation: Patient should refrain from cold medicines, nose drops, and nasal sprays for at least 48 hours prior to test. 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.

Supplies: Urine Tubes, 10 mL (T068)

Collection Container/Tube: Clean, plastic urine collection container

Submission Container/Tube: Plastic, 10 mL urine tube

Specimen Volume: 10 mL

Collection Instructions:

1. Collect a random urine specimen.

2. No preservative.


If not ordering electronically, complete, print, and send a Oncology Test Request (T729) with the specimen.

Specimen Minimum Volume
Defines the amount of sample necessary to provide a clinically relevant result as determined by the Testing Laboratory

3 mL

Reject Due To
Identifies specimen types and conditions that may cause the specimen to be rejected

  All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.

Specimen Stability Information
Provides a description of the temperatures required to transport a specimen to the performing laboratory, alternate acceptable temperatures are also included

Specimen Type Temperature Time Special Container
Urine Refrigerated (preferred) 28 days
Frozen 28 days
Ambient 14 days

Useful For
Suggests clinical disorders or settings where the test may be helpful

A second-order screening test for the presumptive diagnosis of pheochromocytoma in patients with non-episodic hypertension


Confirming positive plasma metanephrine results in patients with non-episodic hypertension

Clinical Information
Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

Pheochromocytoma is a rare, potentially lethal, tumor of chromaffin cells of the adrenal medulla that produces episodes of hypertension with palpitations, severe headaches, and sweating ("spells").


Pheochromocytomas and other tumors derived from neural crest cells (eg, paragangliomas and neuroblastomas) secrete catecholamines (epinephrine and norepinephrine).


Metanephrine and normetanephrine are the 3-methoxy metabolites of epinephrine and norepinephrine, respectively. Both are further metabolized to vanillylmandelic acid.


Pheochromocytoma cells are also able to oxymethylate catecholamines into metanephrines that are secreted into circulation.

Reference Values
Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.



0-2 years: 82-418 mcg/g creatinine

3-8 years: 65-332 mcg/g creatinine

9-12 years: 41-209 mcg/g creatinine

13-17 years: 30-154 mcg/g creatinine

> or =18 years: 29-158 mcg/g creatinine





0-2 years: 121-946 mcg/g creatinine

3-8 years: 92-718 mcg/g creatinine

9-12 years: 53-413 mcg/g creatinine

13-17 years: 37-286 mcg/g creatinine

18-29 years: 53-190 mcg/g creatinine

30-39 years: 60-216 mcg/g creatinine

40-49 years: 69-247 mcg/g creatinine

50-59 years: 78-282 mcg/g creatinine

60-69 years: 89-322 mcg/g creatinine

> or =70 years: 102-367 mcg/g creatinine




0-2 years: 121-946 mcg/g creatinine

3-8 years: 92-718 mcg/g creatinine

9-12 years: 53-413 mcg/g creatinine

13-17 years: 37-286 mcg/g creatinine

18-29 years: 81-330 mcg/g creatinine

30-39 years: 93-379 mcg/g creatinine

40-49 years: 107-436 mcg/g creatinine

50-59 years: 122-500 mcg/g creatinine

60-69 years: 141-574 mcg/g creatinine

> or =70 years: 161-659 mcg/g creatinine





0-2 years: 241-1,272 mcg/g creatinine

3-8 years: 186-980 mcg/g creatinine

9-12 years: 110-582 mcg/g creatinine

13-17 years: 78-412 mcg/g creatinine

18-29 years: 96-286 mcg/g creatinine

30-39 years: 106-316 mcg/g creatinine

40-49 years: 117-349 mcg/g creatinine

50-59 years: 130-386 mcg/g creatinine

60-69 years: 143-427 mcg/g creatinine

> or =70 years: 159-472 mcg/g creatinine




0-2 years: 241-1,272 mcg/g creatinine

3-8 years: 186-980 mcg/g creatinine

9-12 years: 110-582 mcg/g creatinine

13-17 years: 78-412 mcg/g creatinine

18-29 years: 131-467 mcg/g creatinine

30-39 years: 147-523 mcg/g creatinine

40-49 years: 164-585 mcg/g creatinine

50-59 years: 184-655 mcg/g creatinine

60-69 years: 206-733 mcg/g creatinine

> or =70 years: 230-821 mcg/g creatinine

Provides information to assist in interpretation of the test results

Increased metanephrine and normetanephrine levels are found in patients with pheochromocytoma and tumors derived from neural crest cells.


Increased urine metanephrines can be detected in non-pheochromocytoma hypertensive patients; quantification may help distinguish these patients from those with tumor-induced symptoms.

Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

While screening for pheochromocytoma is best accomplished by measuring plasma free fractionated metanephrines (a more sensitive assay), follow-up testing with urinary fractionated metanephrines (a more specific assay) may identify false-positive results. Twenty-four-hour urine collections are preferred, especially for patients with episodic hypertension; ideally the collection should begin at the onset of a "spell."


This test utilizes a liquid chromatography-tandem mass spectrometry method and is not affected by the interfering substances that affected the previously utilized spectrophotometric (Pisano reaction) method (ie, diatrizoate, chlorpromazine, hydrazine derivatives, imipramine, monoamine oxidase inhibitors, methyldopa, phenacetin, ephedrine, or epinephrine).


This method is also not subject to the known interference of acetaminophen, which is seen with the plasma metanephrine high performance liquid chromatography-electrochemical detection 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.

Clinical Reference
Recommendations for in-depth reading of a clinical nature

1. van Duinen N, Corssmit EPM, de Jong WHA, Brookman D, Kema P, Romijn JA: Plasma levels of free metanephrines and 3-methoxytyramine indicate a higher number of biochemically active HNPGL than 24-h urinary excretion rates of catecholamines and metabolites. Eur J Endocrinol. 2013 Aug 28;169(3):377-382 doi: 10.1530/EJE-13-0529

2. Pacak K, Linehan WM, Eisenhofer G, Walther MM, Goldstein DS: Recent advances in genetics, diagnosis, localization, and treatment of pheochromocytoma. Ann Intern Med. 2001 Feb 20;134(4):315-329

3. Sawka AM, Singh RJ, Young WF Jr: False positive biochemical testing for pheochromocytoma caused by surreptitious catecholamine addition to urine. Endocrinologist. 2001;11:421-423

4. Eisenhofer G, Grebe S, Cheung NKV: Monoamine-producing tumors. In: Rifai N, Horvath AR, Wittwer CT, eds. Tietz Textbook of Clinical Chemistry and Molecular Diagnostics. 6th ed. Elsevier; 2018:1421

5. Shen Y, Cheng L: Biochemical diagnosis of pheochromocytoma and paraganglioma. In: Mariani-Costantini R, ed. Paraganglioma: A Multidisciplinary Approach. Codon Publications; 2019. Accessed July 20, 2021. Available at www.ncbi.nlm.nih.gov/books/NBK543224/

6. Hernandez FC, Sanchez M, Alvarez A, et al: A five-year report on experience in the detection of pheochromocytoma. Clin Biochem. 2000 Nov;33(8):649-55. doi: 10.1016/s0009-9120(00)00172-7

7. van Duinen N, Steenvoorden D, Kema IP, et al: Increased urinary excretion of 3-methoxytyramine in patients with head and neck paragangliomas. J Clin Endocrinol Metab. 2010 Jan;95(1):209-14. doi: 10.1210/jc.2009-1632

8. Le Jacques A, Abalain JH, Le Saos F, Carre JL: Significance of 3-methoxytyramine urine measurement in the diagnosis of pheochromocytomas and paragangliomas: about 28 patients. Ann Biol Clin (Paris). 2011 Sep-Oct;69(5):555-9. French. doi: 10.1684/abc.2011.0612

9. Muskiet FA, Thomasson CG, Gerding AM, Fremouw-Ottevangers DC, Nagel GT, Wolthers BG: Determination of catecholamines and their 3-O-methylated metabolites in urine by mass fragmentography with use of deuterated internal standards. Clin Chem. 1979 Mar;25(3):453-60

10. Hirsch D, Grossman A, Nadler V, Alboim S, Tsvetov G: Pheochromocytoma: Positive predictive values of mildly elevated urinary fractionated metanephrines in a large cohort of community-dwelling patients. J Clin Hypertens (Greenwich). 2019 Oct;21(10):1527-1533. doi: 10.1111/jch.13657

Method Description
Describes how the test is performed and provides a method-specific reference

Metanephrine and Normetanephrine:

Urine samples are acidified and hydrolyzed in a heat block; metanephrine and normetanephrine are extracted from the specimens utilizing extraction cartridges. Analyte concentrations are determined through analysis performed by a liquid chromatography-tandem mass spectrometry method.(Unpublished Mayo method)



The enzymatic method is based on the determination of sarcosine from creatinine with the aid of creatininase, creatinase, and sarcosine oxidase. The liberated hydrogen peroxide is measured via a modified Trinder reaction using a colorimetric indicator. Optimization of the buffer system and the colorimetric indicator enables the creatinine concentration to be quantified both precisely and specifically.(Package insert: Creatinine plus ver 2. Roche Diagnostics; V15.0, 03/2019)

PDF Report
Indicates whether the report includes an additional document with charts, images or other enriched information


Day(s) Performed
Outlines the days the test is performed. This field reflects the day that the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time before the test is performed. Some tests are listed as continuously performed, which means that assays are performed multiple times during the day.

Monday through Friday

Report Available
The interval of time (receipt of sample at Mayo Clinic Laboratories to results available) taking into account standard setup days and weekends. The first day is the time that it typically takes for a result to be available. The last day is the time it might take, accounting for any necessary repeated testing.

3 to 5 days

Specimen Retention Time
Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded

2 weeks

Performing Laboratory Location
Indicates the location of the laboratory that performs the test


Several factors determine the fee charged to perform a test. Contact your U.S. or International Regional Manager for information about establishing a fee schedule or to learn more about resources to optimize test selection.

  • Authorized users can sign in to Test Prices for detailed fee information.
  • Clients without access to Test Prices can contact Customer Service 24 hours a day, seven days a week.
  • Prospective clients should contact their account representative. For assistance, contact Customer Service.

Test Classification
Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR) product.

This test was developed, and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the US Food and Drug Administration.

CPT Code Information
Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Clinic Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.

CPT codes are provided by the performing laboratory.



LOINC® Information
Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the order and results codes of this test. LOINC values are provided by the performing laboratory.

Test Id Test Order Name Order LOINC Value
METRN Metanephrines, Fract., Random, U 68317-7
Result Id Test Result Name Result LOINC Value
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
21546 Metanephrine/Creatinine 9645-3
21547 Normetanephrine/Creatinine 13783-6
21548 Total Metanephrine/Creatinine 13771-1
CRETR Creatinine, Random, U 2161-8

Test Setup Resources

Setup Files
Test setup information contains test file definition details to support order and result interfacing between Mayo Clinic Laboratories and your Laboratory Information System.

Excel | Pdf

Sample Reports
Normal and Abnormal sample reports are provided as references for report appearance.

Normal Reports | Abnormal Reports

SI Sample Reports
International System (SI) of Unit reports are provided for a limited number of tests. These reports are intended for international account use and are only available through MayoLINK accounts that have been defined to receive them.

SI Normal Reports | SI Abnormal Reports

Test Update Resources

Change Type Effective Date
Test Status - Test Resumed 2021-11-18
Test Status - Test Delay 2021-11-17
New Test 2021-10-05