Ordering Guidance

This test is not the first-tier test for pheochromocytoma, as plasma catecholamine levels may not be continuously elevated. For the recommended first-tier laboratory test for pheochromocytoma, order either:

-PMET / Metanephrines, Fractionated, Free, Plasma

-METAF / Metanephrines, Fractionated, 24 Hour, Urine

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

Specimen Required

Patient Preparation:

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

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

3. The patient must not eat, use tobacco, or drink caffeinated beverages for at least 4 hours before the specimen is collected.

Supplies:

Catecholamine Tubes-EDTA (T066) (contain sodium metabisulfite, may come as 10-mL or 6-mL tubes, and have a 6-month expiration time)

Sarstedt Aliquot Tube, 5 mL (T914)

Collection Container/Tube:

Preferred: 10-mL Catecholamine tubes containing EDTA-sodium metabisulfite solution

Acceptable: 6-mL Catecholamine tubes containing EDTA-sodium metabisulfite solution

Submission Container/Tube: Plastic vial

Specimen Volume: 3 mL plasma per collection

Collection Instructions:

Note: If the collection instructions are not followed, falsely elevated test results are highly likely.

1. Drawing from a catheter is required.

2. Calm the patient by giving complete instructions and reassurance regarding the procedure.

3. Insert an indwelling intravenous catheter. Flush with 3 mL of saline, using positive pressure.

4. Have the patient rest for 30 minutes in the supine position in a quiet room.

5. At the end of the 30 minutes, withdraw and discard a minimum of 3 mL of blood to remove the saline out of the catheter.

6. If provocative sampling (eg, standing specimen) is required, perform provocative maneuver immediately after obtaining supine specimen. Obtain standing specimen immediately.

7. For each specimen, draw blood into the chilled EDTA-sodium metabisulfite 10-mL tube.

8. Specimens must remain at refrigerated temperature at all times.

9. Within 30 minutes of collection, centrifuge in a refrigerated centrifuge and aliquot plasma into a plastic vial.

10. Freeze specimen immediately. Transport frozen.