Pheochromocytoma (PhC) is a tumor originating from the chromaffin cells of the adrenal medulla, capable of hyperproduction of catecholamines (adrenaline, noradrenaline and dopamine). The importance of early diagnosis of this pathology is associated with the survival of patients due to the risk of developing catecholamine crises, which in turn can cause the development of cardiovascular and cerebral accidents, up to and including death. In the primary diagnosis of pheochromocytomas, it is important to determine the level of catecholamine metabolites – metanephrines. In modern clinical practice, there are different options for laboratory determination of these metabolites: in blood plasma or urine, total amount or only free form, fractionated or unfractionated analysis. As the results of a survey conducted among primary care physicians showed, the choice of diagnostic method and the scope of examination in case of suspected pheochromocytoma/paraganglioma causes difficulties for the majority of respondents. This study was aimed to discussion of the modern methods of pheochromocytoma diagnostics, processes of catecholamine synthesis and metabolism, and the nuances of various laboratory diagnostic methods, the rules for collecting samples and factors that can potentially affect the test results. This, in our opinion, will bring some clarity to the existing problem and provide primary care physicians with a convenient algorithm for laboratory diagnostics of pheochromocytoma.

Keywords: adrenal neoplasms, paraganglioma, metanephrines, pheochromocytoma, catecholamines