Laboratory Services

Metanephrines, Fractionated, 24 Hour, Urine

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Updated Test Information:

Test Description
Metanephrines, Fractionated, 24 Hour, Urine
Synonym(s)

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

Test ID
METAF
General Information

Useful for:



  • A first- and second-order screening test for the presumptive diagnosis of catecholamine-secreting pheochromocytomas and paragangliomas

  • Confirming positive plasma metanephrine results

Specimen Type

24-Hour Urine

Specimen Collection / Processing Instructions

  • Patient Preparation: Tricyclic antidepressants, labetalol, and sotalol medications may elevate levels of metanephrines producing results that cannot be interpreted. If clinically feasible, it is optimal to discontinue these medications at least 1 week before collection. For advice on assessing the risk of removing patients from these medications and alternatives, consider consultation with a specialist in endocrinology or hypertension

  • Collect urine for 24 hours

  • Add 10 g (pediatric: 3 g) of boric acid or 25 mL (pediatric: 15 mL) of 50% acetic acid as preservative at start of collection.

  • See Collection and Transportation for 24-Hour Urine Specimens

Required Information

24-Hour volume is required

Stability

  • Refrigerated (preferred): 28 days

  • Frozen: 28 days

  • Ambient: 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 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 not subject to the known interference of acetaminophen (seen with the plasma metanephrine HPLCEC method)

Methodology

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

Estimated TAT

3-5 days

Testing Schedule

Monday-Friday

Test Includes

  • Metanephrine

  • Normetanephrine

  • Total Metanephrines

Retention

14 days

CPT Code(s)

83835

Additional Information
Minimum Sample Volume

2 mL

Reference Range
Fraction: Metanephrine (mcg/24h) Normetanephrine (mcg/24h) Total Metanephrines (mcg/24h)
Hypertensive < 400 < 900 < 1300
Normotensive: Age (years)* Male Female Male Female Male Female
3 - 8 29 - 92 18 - 144 34 - 169 29 - 145  47 - 223  57 - 210
9 - 12 59 - 188 43 - 122 84 - 422 55 - 277  201 - 528  107 - 394
13 - 17 69 - 221 33 - 185 91 - 456 57 - 286  120 - 603  113 - 414
18 - 29 44 - 261 30 - 180 103 - 390 103 - 390  190 - 583  142 - 510
30 - 39 111 - 419 111 - 419  200 - 614  149 - 535
40 - 49 119 - 451 119 - 451  211 - 646 156 - 561 
50 - 59 128 - 484 128 - 484  222 - 680 164 - 588 
60 - 69 138 - 521 138 - 521  233 - 716  171 - 616
≥ 70 148 - 560 148 - 560  246 - 753 180 - 646 

*Reference values have not been established for patients that are <36 months of age

 

Performing Lab

Mayo

LOINC Code(s)

19049-6, 2671-6, 2609-6, 13362-9, 3167-4, 48767-8