Phaeochromocytoma--a laboratory experience

Thirteen phaeochromocytomas were found over five and a half years from 2,834 patient requests for tumour screens. HMMA (VMA) was the usual screening test requested. Free catecholamines were reported when specifically requested by clinicians and where the HMMA level was > 40 mumol/24 hr. HMMA and urinary free catecholamines were estimated using HPLC with electrochemical detection in acidified 24 hr collections. Noradrenaline was elevated in all thirteen, nine had raised adrenaline and two had raised levels of all three catecholamines. Urinary free catecholamines are the most appropriate analyte package in our circumstances for the diagnosis of phaeochromocytoma. HMMA if used alone could lead to false negative diagnoses but it has a role in minimising false negatives where urinary catecholamine results are normal.