[Garbage in-garbage out: influence of preanalytical variables on hematological analysis]

Preanalytical factors have a significant impact on the quality of hematological analyses and must not be disregarded during clinical interpretation of laboratory data. Besides unchangeable physiological variables such as age, sex, race, patient preparation, an expert phlebotomy, rapid transport to the laboratory as well as many other variable factors play a crucial role in obtaining correct laboratory results. More advanced tests (erythrocyte enzymes, evaluation of hemoglobinopathies, molecular biology, flowcytometric characterization of leucocytes etc.) performed by specialized centers require special preanalytical measures. The centers should be consulted about the preanalytical conditions before blood sampling is performed or--if possible--the patient should be sent to these centers for phlebotomy.