It was the aim of our work to study the perceptivity of coagulation disturbances by discriminant analyses. Altogether 1286 persons had been tested, among them hypotrophic and preterm newborns, newborns with the RDS, with vitamin K deficiency, and with septicemia as well as patients beyond the postnatal period with septic and other diseases. The study was performed in the course of 15 years. Therefore only simple parameters were included. Different combinations of variables were tested, also combinations with clinical data. In patients with vitamin K deficiency about 90 per cent of the findings were classified correctly. About 70 per cent of the septic newborns were recognized in this way, but only 50 per cent of newborns with RDS. But for septicemia during the first 3 days of life a sensitivity of 84 per cent was calculated. For infants and children beyond the postnatal period even lower sensitivity rates were found. After inclusion of clinical data an improvement was obtained for many cohorts. Coagulation findings cannot be interpreted correctly in every case at first sight. Follow-up investigations are a good assistance for the correct classification.