Laboratory Services

Metanephrines, Fractionated, Random, Urine

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Updated Test Information:

Test Description
Metanephrines, Fractionated, Random, Urine
Synonym(s)

Metanephrines free, urine; NMN (Normetanephrines), urine; Normetanephrine, (NMN), free; Normetanephrines, urine; Fractionated metanephrines

Test ID
METAR
General Information

Useful for:



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

  • Confirming positive plasma metanephrine results in patients with nonepisodic hypertension

Specimen Type

Random Urine

Specimen Requirements

Urine Cup

Specimen Collection / Processing Instructions

  • Patient Preparation: 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

  • Collection Container/Tube: Clean, plastic urine collection container

  • Submission Container/Tube: Plastic urine tube

  • Specimen Volume: 5 mL

  • Collection Instructions:

    • Collect a random urine specimen

    • No preservative



Stability

  • Frozen (preferred): 28 days

  • Ambient: 28 days

  • Refrigerated: 28 days

Unacceptable Specimen Conditions

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

Limitations

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

  • This method is also not subject to the known interference of acetaminophen (seen with the plasma metanephrine HPLC-EC 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.

Methodology

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

Estimated TAT

3-5 days

Testing Schedule

Monday-Friday

Test Includes

  • RCTU: Creatinine Conc

  • METAU: Metanephrines, Fractionated

Retention

14 days

CPT Code(s)

83835

Additional Information
Minimum Sample Volume

3 mL

Reference Range
Normotensive Patients

Metanephrine / Creatinine

(mcg/g Creatinine)

Normetanephrine / Creatinine

(mcg/g Creatinine)

Total Metanephrine / Creatinine

(mcg/g Creatinine)

Age (Years) Male Female Male Female Male Female
0 - 2 82 - 418 121 - 946 241 - 1272
3 - 8 65 - 332 92 - 718 186 - 980
9 - 12 41 - 209 53 - 413 110 - 582 
13 - 17 30 - 154 37 - 286 78 - 412
18 - 29 29 - 158 53 - 190  81 - 330 98 - 286 131 - 467
30 - 39  60 - 216 93 - 379  106 - 316 147 - 523
40 - 49 69 - 247  107 - 436  117 - 349 164 - 585
50 - 59 78 - 282  122 - 500 130 - 386 184 - 655
60 - 69 89 - 322  141 - 574 143 - 427 206 - 733
≥ 70 102 - 367  161 - 659 159 - 472 230 - 821

 

 

Performing Lab

Mayo

LOINC Code(s)

9645-3, 2161-8, 13786-6, 13771-1