Factors that influence reference values]

The factors that influence reference values are briefly reviewed using our experimental data. The factors can be divided into the following 3 subfactors: analytical technology, selection of so called healthy person and statistical method. The most large effect came from a variety of physiological conditions in healthy persons, i.e., age, sex, diurnal and menstrual rhythms, drinking and smoking habits, diet, physical exercise, posture, tourniquet etc. A new concept of tow-step reference values "the basal value and the equivocal value" is postulated from the studies of the effect of these physiological conditions. The effects of the statistical methods for obtaining the distribution type of data of normal reference group and the 95% reference range were not so large. Then, we conclude that the reference values or the reference ranges should be made in your own laboratories using carefully selected healthy persons even if 30 or 50 small numbers are used.