There are a variety of biochemical tests for the detection of phaeochromocytoma and functional (secretory) paraganglioma including catecholamines and their methylated metabolites (“metanephrines”; metanephrine and normetanephrine) and 3-methoxytyramine. Plasma, serum, or urine can be used.
We recommend following the Endocrine Society Clinical Practice Guidelines for biochemical screening for paraganglioma/phaeochromocytoma (PPGL):
- Measure plasma free or urinary fractionated metanephrines
- If available also measure 3-methoxytyramine
- Collect plasma samples after the patient has rested in the supine position for 10-20 minutes preferably due to an increase in false positivity rate with seated measurements. If supine measurements are not practical the test can be performed in the seated position and repeated in the supine position in patients with mildly abnormal results.
- In certain circumstances repeat sampling may be recommended by the referring clinician; if this occurs collection after 30 minutes of rest in the supine position may be appropriate
- If measuring plasma 3-methoxytyramine, sampling should be done after an overnight fast.
- Preference for LCMS/MS assay method as this minimises analytical interference with some drugs, and for plasma for convenience. More than a two-fold increase above the upper cut-offs of reference intervals provides a high suspicion for PPGL in an at risk individual.
For more information see advice for patients having tests to measure biogenic amines.