Automated measurement of two indicators of human selenium status, and applicability to population studies

We developed an automated system consisting of a centrifugal analyzer and an atomic absorption spectrophotometer with Zeeman background correction to produce a profile of the concentrations of selenium and the selenium-dependent enzyme glutathione peroxidase (EC 1.11.1.9) in serum and whole blood, for use in epidemiological surveys in Northern Ireland. No pretreatment of samples other than dilution is required, and at least 35 subjects can be screened within 24 h of venesection. For selenium in serum the between-run CV was 5.7% and 4.4% within run. For selenium in whole blood the CV was 5.9% between runs, 5.7% within run. The within-run CV for glutathione peroxidase was 0.92% for serum, 1.18% for blood; the between-run CV was 8.3% for serum. To illustrate the use of the system, we present the profile of selenium and glutathione peroxidase in serum and whole blood from 100 adults 25 to 64 years old.