PHEOCHROMOCYTOMA - 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 s creening test requested. Free catecholamines were reported when specif ically 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. Noradr enaline was elevated in all thirteen, nine had raised adrenaline and t wo had raised levels of all three catecholamines. Urinary free catecho lamines 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 nega tives where urinary catecholamine results are normal.