Providing Correct Estimates of Biological Variation-Not an Easy Task. The Example of S100-beta Protein and Neuron-Specific Enolase - Carobene, Anna; Guerra, Elena; Locatelli, Massimo; Ceriotti, Ferruccio; Sandberg, Sverre; Fernandez-Calle, Pilar; Coskun, Abdurrahman; Aarsand, Aasne K.; Chem, European Federation Clinical; Variation, Working Grp Biological (AMER ASSOC CLINICAL CHEMISTRY, 2018)