Can age and sex related reference intervals be derived for non-healthy andnon-diseased individuals from results of measurements in primary health care?

Reference intervals in clinical chemistry are commonly based on results of measurements in reference populations or are taken from the literature. A r eference population should represent a defined group of individuals and be as similar as possible to the patients under investigation. Frequently, ref erence populations have been recruited from institutionalised healthy young people who do not necessarily fulfill these criteria. In the present study we describe the temporal changes in 37 commonly measured quantities in men and women from childhood to late in life. The samples were collected in th e primary health care and sorted according to an assumed decision by the ph ysician. The emerging group of individuals forms a reference population tha t was regarded as "non-diseased" and the results of measurements in this po pulation are reference values. A remaining group of "non-healthy" were like wise identified for comparison. The central 95 percentile was wider than th ose usually assigned to the quantities whereas the medians almost coincided . In the "non-healthy" group the medians were shifted in a direction that w ould be expected from pathophysiology aspects.