Review

Abstract

Different results are usually observed when a quantity is measured in different specimens from the same individual obtained over a time span. For an individual, this variation is due to the imprecision of the measurement procedure, that is to say the metrological variability, as well as to the rhythmic and random fluctuations of the quantity value around a virtual homeostatic set point, that is to say the intra-individual biological variability.On the other hand, when studying the intra-individual biological variation of a quantity a mean value, the virtual homeostatic set point, is estimated for each individual participating in the study. The variation among these mean values is due to the inter-individual biological variability.Sebasti n-G mbaro et al.: Biological variability bank Tab. 1 Medians of the coefficients of intra-individual (med CV Bw ) and inter-individual (med CV B b) biological variation of biological quantities in healthy subjects estimated in different studies with different time spans. The symbols used in this table are: h = hour; d = day; wk = week; mo = month; a = year; p = mass concentration; b = catalytic con-centration; m = mass; c = substance concentration; κ/Ν = entitle amount of substance; η = amount of substance; ρ = partial pressure; orb = arbitrary; t = time; C = number concentration; φ = volume fraction; VfN = entitle volume; V = volume; χ = substance fraction; / = length; ζ = catalytic activity; δ = number fraction; NO = no data available.