The clinical relevance of factor VIII: C and factor VII R: Ag determination in newborns.

Higher levels of factor VIII: C and factor VIII R: Ag were found in healthy newborns (n = 60) as compared to adults. This could be explained as a stress reaction due to birth and the adaptation to extrauterine life. A further stress factor is disease. The highest values for factor VIII R: Ag were found in ill (n = 32) and in severely ill newborns (n = 21). The large ranges of factor VIII: C and of the ratio of factor VIII: C/VIII R: Ag in healthy newborns can be explained by an increased turnover of coagulation factors. Diseases in the newborn period lead to an increase of this process, resulting in even larger ranges of factor VIII: C and of the ratio of factor VIII: C/VIII R: Ag in ill and extremely ill newborns. Consumption of factor VIII: C with a low ratio of factor VIII: C/VIII R: Ag predominates in extremely ill newborns. The ratio of factor VIII: C/VIII R: Ag is more valuable than factor VIII: C for diagnosis of DIC in newborns. A diagnosis of hemophilia and von Willebrand's disease cannot be established with certainty in severely ill newborns. Stress and DIC may influence the characteristic changes of laboratory parameters.