Hemostasis evaluation in childhood (excluding newborns).

There are three different aspects in the etiological diagnosis of hemostasi s disorders: (1) primary hemostasis evaluation; (2) coagulation evaluation; and (3) thrombosis evaluation. In every case, a look at medical history is an essential step before proceeding to biological investigations. Bleeding time is the first step of the primary hemostasis evaluation; prolonged dru g use (particularly salicylates) and thrombocytopenia must be first conside red only then will the Von Willebrand factor and platelet functions be stud ied. Coagulation evaluation first requires the study of the overall coagula tion tests (Quicks test, partial thromboplastin time test and thrombin time test); determination of the different plasma coagulation factors and searc h for a circulating anticoagulant will be performed secondarily, allowing d ifferentiation between the different acquired or constitutional coagulation disorders. Thrombosis evaluation must first consider a local or general in citing factor before looking for anti-phospholipid antibodies, an acquired protein C or S deficiency or a constitutional hemostasis disorder. (C) 1999 Editions scientifiques et medicales Elsevier SAS.