Test Directory

• Metanephrine
• Normetanephrine

Evaluation of catecholamine-secreting tumors of the adrenal medulla (pheochromocytomas) and extra-adrenal sympathetic and parasympathetic paragangliomas.

Specimen Type: 24 Hour Urine

Collection Container: 24 Hour Plastic Urine Container

Desired Specimen Volume: 10 mL

1. Collect 24-hour in a timed collection kit.
2. Specimen must be collected in a plastic container and refrigerated during collection.

1. Transport 10 mL of urine in the original collection container or transfer to clear aliquot tubes (screw cap).
2. Record total volume and collection time interval on transport tube and test request form.
   • HNL Lab Medicine 24-Hour Urine Collection

No caffeine before or during collection. Monamine oxidase inhibitors should be discontinued at least one week prior to beginning collection.

Transport to the laboratory refrigerated. 

 See patient report.

The low prevalence of PPGL combined with the limited diagnostic specificity of the metanephrine test means that false-positive results far outnumber true-positive results.15,27 As outlined in the Endocrine Society Guidelines,15 all patients with positive test results should receive appropriate follow-up according to the extent of increased values and clinical presentation of the patient. The nature of this follow-up is a matter of clinical judgment based on the pretest probability of tumor and the extent and pattern of increases in test results.

A number of medications and foods should be considered as potential causes of borderline elevations of plasma metanephrine and/or normetanephrine.2,5,27,28,32,33 These include:

• selective serotonin and norepinephrine reuptake inhibitors (SSNRIs)

• tricyclic antidepressants

• alpha blockers

• beta blockers

• monoamine oxidase inhibitors

• caffeine

• cigarette smoking

• strenuous exercise

Confirmatory testing after exclusion of these and other sources of false-positive results is often useful for ruling out disease.

• Metanephrines, Fractionated, Quantitative, 24-Hour Urine