Study of seasonal behavior in erythrocyte sedimentation rate (ESR).

The ESR is used as a common human clinical laboratory test which allows identification in the presence and intensity of active pathologies. In this paper, the seasonality of the variable was described and modelled. Monthly means and medians of a transformation of this variable were used. Nonparametric smoothing techniques and cumulative periodograms permitted to describe the seasonal behavior, and parametric models allowed to demonstrate its significance.