METANEPHRINES, FRACTIONATED, URINE, 24 HOUR

Test Documentation
Specimen Required
Collect 24 hour urine (see collection instructions below). Send 25 mL acidified urine (10.0 mL minimum) refrigerated in a screw-capped plastic urine container. Record total volume on test requisition and specimen label.
24 hour urine collection: The bladder must be emptied at the time the collection is to begin, and this urine is discarded. Thereafter all urine must be collected until the end of the scheduled time.
Preferred method of collection for 24 hour collection: Collect urine with 6N HCl at start of collection to maintain pH between 1 and 3. Refrigerate urine during collection (critical). Mix the collection well before removing aliquot. Record total volume on test request and on container label. Send refrigerated 25 mL aliquot (10 mL minimum).
NOTE: Medications that may interfere with metanephrine include amphetamines and amphetamine-like compounds, appetite suppressants, bromocriptine, buspirone, caffeine, carbidopa-levopa (Sinemet), clonidine, dexamethasone, diuretics (in doses sufficient to deplete sodium), methyldopa (Aldomet), MAO inhibitors, nose drops, propafenone (Rythmol), trycyclic antidepressants, and vasodilators.

Alternate Specimen
Alternate method of collection for 24 hour collection: Refrigerate urine during collection (critical) and add 25 mL 6N HCl to the entire collection within 4 hours of completing collection. Mix the collection well before checking the pH. Ensure pH is between 1-3. Record total volume on test request and on container label. Send refrigerate 25 mL aliquot (10 mL minimum).
If other tests are ordered requiring pH other than 1-3 you may acidify a 25.0 mL aliquot from the 24 hour collection.

Methodology
High Performance Liquid Chromatography

Stability
With preservative: Room Temperature: 7 days; Refrigerated: 7 days; Frozen: 7 days
Without preservative: Room Temperature: 7 days; Refrigerated: 7 days; Frozen: 7 days
Preservative must be added before sample is submitted for testing.

Reference Range
Metanephrine:
   Age   Range  
   0-3 months   6-37 mcg/day  
   4-6 months   6-42 mcg/day  
   7-9 months   12-41 mcg/day  
   10-12 months   9-101 mcg/day  
   1-2 years   7-52 mcg/day  
   3-6 years   11-99 mcg/day  
   7-10 years   54-138 mcg/day  
   11-16 years   39-242 mcg/day  
   >=17 yrs   52-341 mcg/day  
Normetanephrine:
   Age   Range  
   0-3 months   47-156 mcg/day  
   4-6 months   31-111 mcg/day  
   7-9 months   42-109 mcg/day  
   10-12 months   23-103 mcg/day  
   1-2 years   32-118 mcg/day  
   3-6 years   50-111 mcg/day  
   7-10 years   47-176 mcg/day  
   11-16 years   53-290 mcg/day  
   >=17 years   88-444 mcg/day  
Total Metanephrines:
   Age   Range  
   0-3 months   53-193 mcg/day  
   4-6 months   37-153 mcg/day  
   7-9 months   54-150 mcg/day  
   10-12 months   32-204 mcg/day  
   1-2 years   39-170 mcg/day  
   3-6 years   61-210 mcg/day  
   7-10 years   101-314 mcg/day  
   11-16 years   92-532 mcg/day  
   >=17 years   140-785 mcg/day  
Creatinine:
   Male:   0.1-2.0 g/24 hrs  
   Female:   0.8-1.8 g/24 hrs  

Performed
Setup: Monday, Wednesday, Friday
Reported: 2-4 days

Turnaround Time4-6 days
Test CodeUMET
CPT-4 Code (s)
83835, 82570
LOINC Codes
Hours collected   30211-7  
Total volume   19153-6  
Normetanephrine   2671-6  
Metanephrine   19049-6  
Total metanephrines   2609-6  

Warde
Medical
Laboratory