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Test Code Billings Clinic: 8819 Mayo: CATU Catecholamine Fractionation, Free, 24 Hour, Urine

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Reporting Name

Catecholamine Fract, Free, U

Useful For

An auxiliary test to fractionated plasma and urine metanephrine measurements in the diagnosis of pheochromocytoma and paraganglioma

 

An auxiliary test to urine vanillylmandelic acid and homovanillic acid determination in the diagnosis and follow-up of patients with neuroblastoma and related tumors

Method Name

High-Performance Liquid Chromatography (HPLC)
Includes unconjugated epinephrine, norepinephrine, and dopamine


Advisory Information


This assay is of greatest value when the specimen is collected during a hypertensive episode.

 

Unless the purpose of the measurement is drug monitoring, discontinue any epinephrine, norepinephrine, or dopamine injections or infusions for at least 12 hours before specimen draw.

 

Do not perform the test on patients withdrawing from legal or illegal drugs known to cause rebound catecholamine release during withdrawal (see Cautions for details)



Necessary Information


24-Hour volume is required.



Specimen Required


Patient Preparation: Discontinue drugs that release or hinder metabolism of epinephrine, norepinephrine, or dopamine for at least 1 week before obtaining the specimen (see Cautions for details). If this is not possible for medical reasons, contact the laboratory to discuss whether a shorter drug-withdrawal period may be acceptable.

Supplies: Plastic, 10-mL urine tube (T068)

Specimen Volume: 2 mL

Collection Instructions:

1. Collect urine for 24 hours.

2. Add 25 mL of 50% acetic acid as preservative at start of collection. Use 15 mL of 50% acetic acid for children less than 5 years old. This preservative is intended to achieve a pH of between approximately 2 and 4.

Additional Information: See Urine Preservatives-Collection and Transportation for 24-Hour Urine Specimens in Special Instructions for multiple collections.


Specimen Type

Urine

Specimen Minimum Volume

1.5 mL

Urine Preservative Collection Options

Ambient

No

Refrigerate

OK

Frozen

OK

50% Acetic Acid

Preferred

Boric Acid

OK

Diazolidinyl Urea

No

6M Hydrochloric Acid

OK

6M Nitric Acid

OK

Sodium Carbonate

No

Thymol

No

Toluene

No

Specimen Stability Information

Specimen Type Temperature Time Special Container
Urine Refrigerated (preferred) 7 days
  Frozen  14 days
  Ambient  7 days

Reject Due To

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

Reference Values

NOREPINEPHRINE

 <1 year: <11 mcg/24 hours

1 year: 1-17 mcg/24 hours

2-3 years: 4-29 mcg/24 hours

4-6 years: 8-45 mcg/24 hours

7-9 years: 13-65 mcg/24 hours

≥10 years: 15-80 mcg/24 hours

 

EPINEPHRINE

 <1 year: <2.6 mcg/24 hours

1 year: <3.6 mcg/24 hours

2-3 years: <6.1 mcg/24 hours

4-9 years: 0.2-10.0 mcg/24 hours

10-15 years: 0.5-20.0 mcg/24 hours

≥16 years: <21 mcg/24 hours

 

DOPAMINE

<1 year: <86 mcg/24 hours

1 year: 10-140 mcg/24 hours

2-3 years: 40-260 mcg/24 hours

≥4 years: 65-400 mcg/24 hours

 

For SI unit Reference Values, see https://www.mayocliniclabs.com/order-tests/si-unit-conversion.html

Interpretation

Diagnosis of Pheochromocytoma:

This test should not be used as the first-line test for pheochromocytoma. PMET / Metanephrines, Fractionated, Free, Plasma (the most sensitive assay) and/or METAF / Metanephrines, Fractionated, 24 Hour, Urine (almost as sensitive and highly specific) are the recommended first-line laboratory tests for pheochromocytoma.

 

However, urine catecholamine measurements can still be useful in patients whose plasma metanephrines or urine metanephrines measurements do not completely exclude the diagnosis. In such cases, urine catecholamine specimens have an 86% diagnostic sensitivity when cut-offs of >80 mg/24 hour for norepinephrine and >20 mg/24 hour for epinephrine are employed. Unfortunately, the specificity of these cut-off levels for separating tumor patients from other patients with similar symptoms is only 88%. When more specific (98%) decision levels of >170 mg/24 hours for norepinephrine or >35 mg/24 hours for epinephrine are used, the assay’s sensitivity falls to about 77%.

 

Diagnosis of Neuroblastoma:

Vanillylmandelic acid, homovanillic acid, and sometimes urine catecholamine measurements on spot urine or 24-hour urine are the mainstay of biochemical diagnosis and follow-up of neuroblastoma; 1 or more of these tests may be elevated.

Day(s) and Time(s) Performed

Monday through Saturday; 8 a.m.

Test Classification

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 U.S. Food and Drug Administration.

CPT Code Information

82384

LOINC Code Information

Test ID Test Order Name Order LOINC Value
CATU Catecholamine Fract, Free, U 92938-0

 

Result ID Test Result Name Result LOINC Value
TM48 Collection Duration 13362-9
VL46 Urine Volume 3167-4
2106 Norepinephrine 2668-2
2107 Epinephrine 2232-7
2108 Dopamine 2218-6

Forms

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