Excretion of free catecholamines by children.

Excretion of free noradrenaline, adrenaline and dopamine were studied in random urine samples from 221 children (123 boys and 98 girls). The group was subdivided according to age, from birth to 12 years. The catecholamines were analysed by liquid chromatography with electrochemical detector using a 5 microns C-18 Novapack column at 32 degrees C. The values were expressed per kilogram of creatinine. A statistical analysis (non-paired t-test) was carried out in order to define the different reference groups. Children under 2 years were found to have higher noradrenaline excretion than other ages; children under 4 years had higher adrenaline excretion than other ages. Children under 3 years had the highest dopamine excretion, followed by children between 3-6 years, while children from 7 to 12 had the lowest excretion. Appropriate reference intervals were determined from the results.