 Control Group Two hundred and fifty subjects will be enrolled in the Control Group; 30 subjects will be included in the pilot study. Considering the rule of thumb that requires a minimum sample size of 120 for the study of reference intervals, the proposed sample size of 250 seems definitely adequate. Nevertheless, the pilot study will allow to have a clearer view of the application of the parametric method. The sample size of the control group could therefore be resized based on preliminary data from the Pilot Study. 