Metanephrines, Fractionated, Plasma Free
Also known as: Metanephrine, Normetanephrine, Plasma Metanephrines, Quantitative Metanephrines
Use
Evaluation of catecholamine-secreting tumors of the adrenal medulla (pheochromocytomas) and extra-adrenal sympathetic and para-sympathetic paragangliomas.
Special Instructions
For centers where sampling in the fully recumbent, supine position is not possible, testing for 24-hour urine metanephrines may be preferable. Blood should be drawn in a chilled lavender-top (EDTA) tube, mixed with preservatives, centrifuged, and the plasma transferred to a labeled plastic transport tube. Sample collection should occur while the patient is in a fully recumbent position for at least 20 minutes before and during sample collection.
Limitations
The low prevalence of PPGL combined with the limited diagnostic specificity means false-positive results far outnumber true-positive results. Inappropriate sampling conditions and a number of medications and foods should be considered potential causes of borderline elevations. All patients with positive test results should receive appropriate follow-up based on the pretest probability of tumor and test result patterns. Confirmatory testing after exclusion of false-positive result sources is often useful for ruling out disease.
Methodology
Mass Spectrometry
Biomarkers
LOINC Codes
- 38494-1
- 2669-0
- 38494-1
Result Turnaround Time
3-6 days
Related Documents
For more information, please review the documents below
Specimen
Plasma
Volume
1.2 mL
Minimum Volume
0.7 mL
Container
Lavender-top (EDTA) tube
Collection Instructions
Draw blood in chilled lavender-top (EDTA) tube. Invert to mix with preservatives. Centrifuge and transfer the plasma to a labeled plastic transport tube. Refrigerate or freeze separated plasma immediately. The patient should be in a fully recumbent position for at least 20 minutes before and during sample collection.
Patient Preparation
Patient should be fasting overnight. Avoid alcohol, coffee, tea, tobacco, and strenuous exercise prior to collection.
Storage Instructions
Sample must be refrigerated due to limited stability at room temperature. Freeze if unable to maintain refrigerated.
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | Unstable |
| Refrigerated | 14 days |
| Frozen | 14 days |