The reference values of the most commonly used parameters in hematology were evaluated in a metaanalysis using practices of a group of major hospitals in Switzerland and in detail review of the literature. Extensive differences of the reference values have been noted being caused mainly by selection of different patient/control collectives. Whenever possible, reference values were separately evaluated for age, gender and race. The reported reference values approximated a Gauss distribution allowing for statistical evaluation accordingly. Due to recent standardization (ICSH and NCCLS), differences caused by instrumentation and preanalytics were found to be of less importance. Our presented validated reference values in hematology should allow for better discrimination of classical hematological disease entities such as an iron deficiency anemia, thalassemia and hemolysis.