[Reference ranges in geriatrics: a review of age-dependence of selected blood components].

An age dependency of blood components is well documented especially in childhood. Less investigated is the situation in the elderly population. Study of the literature and our own investigations show that concentrations of several analytes remain constant throughout adulthood, but many of them increase or decrease with age. The interindividual variability of most parameters is higher in elderly people than in younger adults. Therefore, it is not recommended at the present time to use special adapted reference intervals, because the larger variation of values in higher ages could be affected by the inclusion of diseased individuals in the reference population. Also in high ages, where biochemical individuality is largely maintained, intraindividual reference ranges should be preferred. Thus, latent diseases could be detected much earlier than by transversal evaluation of data.