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Due to their complex preanalytics coagulation tests show a higher rate of rejected samples due to insufficient quality and a higher intra- and inter-individual test variability. In the last years several guidelines addressed this issue in an effort to standardize preanalytic procedures. However, in daily laboratory work, these guidelines frequently cannot be fully executed, due to technical limitations or sample transport logistics. In this manuscript several important issues in sample collection, handling and transportation will be discussed. Since the stability and variability of routine coagulation tests such as prothrombin time and partial prothrombin time are significantly influenced by a number of variables such as tube type, manufacturer, reagents used and analyzer systems, it is recommended that each laboratory develops its own manuals for sample collection, based on published data and internal evaluations.

A survey is given on the value of the haematologo-morphological examination methods, especially the differential counting of leucocytes, the smear of a concentrate of leucocytes and the cytomorphological judgment of the bone marrow. None of these methods is suitable for the search for cases in the sense of a preliminary diagnosis. This is also of importance especially for the differential counting of leucocytes. However, with aimed methods of proceeding these methods are of great diagnostic value, so that they may be very much in front in a graduated diagnostic program. The diagnostic evidence of a cytomorphological preparation of the bone marrow must highly be estimated concerning a situation of deficiency of iron, a diffuse or small nodular metastasizing of the bone marrow or lesion of the bone marrow by exogenic factors.