Catecholamines (24-hour urine)

General Information

Secretory neuroendocrine tumors are usually associated with much higher levels of catecholamines than the upper limit of the established norm.

Pheochromocytoma The most common catecholamine-secretory (adrenaline and noradrenaline) is a tumor, which in 90% of cases is located in the medullary (brain) part of the adrenal gland. This type of tumor can occur alone or in the form of multiple endocrine neoplasms. The clinical picture includes hypertension, often marked by paroxysmal attacks, accompanied by tachycardia, chest pain, paleness, headache, nausea.

Other types of tumors that can occasionally cause paroxysmal or persistent hypertension are: Paraganglioma.

The test contains 3 fractions of free catecholamines (unconjugated) (adrenaline, noradrenaline and dopamine) in 24-hour urine and is an informative tool for diagnosing pheochromocytoma and other tumors of neural origin.

It is usually used as a confirmatory test if an elevated amount of methanephrine is detected in plasma or urine.

The diagnostic value is higher if samples are taken during a hypertensive crisis. Because the production of catecholamines by tumor cells is interrupted, the determination of catecholamines in 24-hour urine is more informative than testing them in plasma.

When should we test for catecholamines?

• Diagnosis of pheochromocytoma;
• Differential diagnostics of arterial hypertension;
• Identify dysfunction of the sympathoadrenal system.

How to prepare for the test?

• It is recommended to avoid: physical and emotional stress, intense physical activity and coffee consumption before taking a urine sample.
• 2 weeks before it is advisable to discontinue medications that may affect the test: Antihypertensive drugs (reserpine, alpha-methyldopa, alpha and beta-blockers), levodopa, monoamine oxidase inhibitors, tricanazine, prespecitine antidepressants.
• When passing the test, it is necessary to use a 25% solution of HCl, in the amount of 10 ml. (You can pick up a supplement at the branch).

Sampling:

• 24-hour urine: At 7 o'clock in the morning the patient urinates and does not urinate; Then collect all the urine in a clean 2-3 liter container until 7 o'clock the next morning. It is necessary to stir the collected urine (for the purpose of homogenization); Measures the whole number; For analysis it takes approx. 10 ml once in a special plastic container. The sample is stored at 2-8ºC during collection and after it is actually processed.

Container required for collection: 2-3 liter container and disposable plastic cup for urine, on which is placed (marked) the total amount of urine in 24 hours.

Possible interpretation of the results

Increased levels of catecholamines in the urine:

• Catecholamine-secreting tumors of neurochromaffin tissue: pheochromocytoma, paragangiloma, neuroblastoma, ganglioneuroma (neuroblastoma, ganglioneuroma is not associated with an increase in adrenaline);
• Intense physical activity;
• Hypertensive crisis;
• Stress;
• Hypoglycemia;
• Acute myocardial infarction