Preanalytical factors and their influence on analytical duality specifications

Whereas analytical standards are described by established quality control c riteria, no such standards exist for defining the quality of the preanalyti cal phase. A working group of the German Society for Clinical Chemistry and Laboratory Medicine has defined recommendations to describe the quality cr iteria for materials and processes used in the diagnostic process between p atients and the analytical step. Thus, the quality of the sample may be def ined regarding its adequacy and amount, as well as anticoagulants and stabi lizers used. Timing of sampling, transport and storage involve criteria on sample stability, proper transport and preanalytical treatment. Moreover, s ample identification, storage, and handling of interference and influence f actors can be documented in quality manuals for the preanalytical phase. Th ese possible variables have been discussed in five European expert meetings and recommendations published in national journals and presented in book f orm.