FRACTIONATED METANEPHRINES - (U)

Test Code: MNPH

Test Indications:
Elevation of Metanephrine and/or Normetanephrine about 2 to 50-fold the upper limit of normal are typically seen in pheochromocytoma.  False-positive tests for pheochromocytoma may be seen in patients on antipsychotic medications.  The neuroleptic malignant syndrome may also be seen in some patients on neuroleptic drugs including the newer agents currently available.  Medications reported to cause false-positive testing for pheochromocytoma include acetaminophen, phenoxybenzamine, amitryptyline, labetolol, haloperidol, levodopa, tamsulosin, venlafaxine, hydrochlorothiazide, buspirone, lamotrigine, and aripiprazole.

Random urines with or without acid preservative are acceptable.  Samples preserved with 6N HCl are acceptable when other tests requiring preservative are ordered on same collection.

_SH Urine Testing Requisition (R250-10-95)

AGE                 MNPH               NMNPH
Units in μmol/mmol creat           (m=male; f=female)
 
0 - 1 mo:           < 0.8                 < 5.0
2 - 3 mo:           < 0.5                 < 3.0
4 - 6 mo:           < 0.4                 < 1.7
7 - 12 mo:         < 0.3                 < 1.2
13 - 36 mo:       < 0.2                 < 0.6
3 - 8 y:              < 0.19               < 0.44
9 - 40 y:            < 0.12               < 0.26
41 - 70 y:          < 0.16               < 0.35 (m)         < 0.40 (f)
Over 70 y:         < 0.20               < 0.40 (m)         < 0.45 (f)

Within 10 Days

Specimen Handling:
Analysis includes separate determinations for metanephrine and normetanephrine.
 
Performed at Health Sciences Centre by Shared Health  Biochemical Genetics Laboratory using UPLC/MS/MS.  This is a laboratory developed test.