Summary A semiautomated method is presented for the determination of adrenaline and noradrenaline by a combination of the trihydroxyindole procedure for total catecholamines and a new procedure for the specific direct determination of adrenaline without interference from noradrenaline at physiological levels. This new procedure involves the reaction of adrenaline with alkaline thiosemicarbazide to produce a fluorophor of acceptable stability for use in automated procedures. Its structure is as yet unknown. The within-batch standard deviation for the trihydroxyindole and alkaline thiosemicarbazide procedures respectively were 0005 μmol/24h at a concentration of 0·368 μmol/24h and 0·012 μmol/24h at a concentration of 0·133 μmol/24h. The between-batch standard deviations of the two procedures were respectively 0·018 μmol/24h at a concentration of 0·388 μmol/24h and 0·015 μmol/24h at a concentration of 0·111 μmol/24h. Normal ranges for urine are presented for 24 healthy ambulant laboratory staff. The total catecholamine concentration (calculated as adrenaline) was 0·452 ± 0·069 μmol/24h (SD), range 0·349–0·616 μmol/24h. Using the alkaline thiosemicarbazide procedure, the normal range which was determined for adrenaline was 0·100 ± 0·054 μmol/24h, range 0·022–0·207 μmol/24h. Noradrenaline calculated by difference was 0·355 ± 0·081 μmoL/24h, range 0·195–0·497 μmol/24h.
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