Summary
It should be realized that the quality of oral anticoagulation depends on thorough
pharmacological knowledge of coumarin congeners, skilled clinical supervision of the
patient and well-standardized laboratory control of patients’ blood. Results of the
laboratory control should no longer be expressed in terms of conventional prolongation
ratios or percentages only. Exact data as to laboratory standardization with reference
plasmas and the results of translation into terms of reference thromboplastins have
to be given.