Reference values for the trace elements copper, manganese, selenium, and zinc in the serum/plasma of children, adolescents, and adults.

Up to now few plasma or serum reference or serum reference values have been available for the assessment of the essential trace element supply status in different age groups covering the whole range of life range. In the present investigation, the concentrations of copper, manganese, selenium, and zinc were determined in the serum of 137 healthy children and in the plasma of 68 blood-donors. The age distribution within these groups ranged from 1 month to 18 years and from 22 to 75 years. The determinations were carried out directly by means of electrothermal atomic absorption spectrophotometry with Zeeman background compensation. The adult plasma reference values (mean +/- 2 SD) were 1.65 +/- 8.6 mumol/1 for copper, 14.3 +/- 11.4 nmol/1 for manganese, 0.80 +/- 0.36 mumol/1 for selenium, and 16.6 +/- mumol/1 for zinc. No correlation between concentration of elements and sex could be established. In the child and adolescent group, the manganese levels exhibited an age-dependent linear decrease (54% of the starting value, slope 0.92, r = 0.4, p < 0.001), the copper and the selenium concentrations, respectively, exhibited an exponential increase (107%, r = 0.59 and 174%, r = 0.61), with the highest value in the age group of 6 to 10 years. Reference ranges are established for 9 different age groups. The results reflect the known physiological data on the trace element content in the tissue of children and their diet. The present study is an important pre-requisite for diagnosis and therapy of trace element deficiencies in all age groups.