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We also are confronted from time to time with the borderleine elevated catecholamine result using ASTED. Our reference intervals (0.95 interfractile) are based on a worse case scenario in that they were derived from a general hospital and GP population following exclusion of patients with proven phaeo and exclusion of outliers using appropriate statistical techniques. The population would appear appropriate since it includes the usual rag bag of patients with hypertension (treated and untreated), funny turns and banana addicts. This is the type of population we screen in general. By the time that most patients are being investigated for the presence of phaeo, the majority have usually become acquainted with the contents of the British Pharmacopoeia and we now fortunately have a reasonable library of chromatograms from subjects taking a variety of cocktails. The operators of the system are very quick to highlight elevated catecholamines, strange peaks, shoulders etc. We find that the main comments that append reports tend to be individualised, and are usually appended with a request for drug information and a requirement for the requesting physician to contact the lab to discuss the case. The chromatograms have a built in safety feature in that they also show the free metadrenalines, and we are very suspicious if the apparrently high noradrenaline output is not associated with a high normetadrenaline peak (this can happen in phaeo however). We find we can explain many of the non-phaeo related elevations in terms badly timed urine collections, drug interferences and specimens collected at inappropriate times (in CCU on the day the patient had MI for instance). We routinely measure urine creatinines to catch some of the funny collections, and also use plots of the sum of creatinine corrected 24h urinary free noradrenaline and adrenaline outputs against creatinine corrected free dopamine outputs in some cases (see attached PowerPoint Slide (95)). We have shown that there is a significant positive correlation between these indices, and that patients with phaeochromocytoma show a positive deviation from the regression line applying to the reference population. The positive deviation is lost post tumour resection. Furthermore, I have had cases in which the urinary free catecholamine excretion has fallen within the conventional population reference intervals, but demonstrated a positive deviation from the line. This may have been due to a deficiency in the collection. I can now expect some flack from some individuals about the problems generated when you start measuring dopamines, but we think there are some good reasons to measure it. On another note, I recall giving a talk on this subject at one centre and was accused of being agressive when I suggested to a speaker that his observation that there group didn't miss any cases of phaeochromocytoma, using only HMMA as a screening test, was fallacious. It has to be accepted that the biological systems that we investigate present us with a continuum ranging from normality to abnormality. It would seem reasonable to assume the more dynamic and responsive that is being investigated, the less categorical in our interpretations and comments. The sympathetic nervous system would appear to present us with one such system (ask Rover). <<Pheagrph.ppt>> Dr WA Bartlett Consultant Clinical Scientist Clinical Biochemistry Birmingham Heartlands Hospital Birmingham B9 5SS Tel. No. 0121 766 6611 Ext 5461. Mobile 0374 103338