The tremendous advances over the past two decades in both clinical genetics and biochemical testing of chromaffin cell tumors have led to new considerations about how these aspects of laboratory medicine can be integrated to improve diagnosis and management of affected patients. With germline mutations in 15 genes now identified to be responsible for over a third of all cases of pheochromocytomas and paragangliomas, these tumors are recognized to have one of the richest hereditary backgrounds among all neoplasms. Depending on the mutation, tumors show distinct differences in metabolic pathways that relate to or even directly impact clinical presentation. At the same time there has been improved understanding about how catecholamines are synthesized, stored, secreted and metabolized by chromaffin cell tumors. Although the tumors may not always secrete catecholamines it has become clear that almost all continuously produce and metabolize catecholamines. This has not only fuelled changes in laboratory medicine, but has also assisted in recognition of genotype-biochemical phenotype relationships important for diagnostics and clinical care. In particular, differences in catecholamine and energy pathway metabolomes can guide genetic testing, assist with test interpretation and provide predictions about the nature and behavior of the tumors. Conversely, results of genetic testing are important for guiding how routine biochemical testing should be employed and interpreted in surveillance programs for at risk patients. In these ways there are emerging needs for modern laboratory medicine to seamlessly integrate biochemical and genetic testing into the diagnosis and management of patients with chromaffin cell tumors.