[Factor XII deficiency - Hageman trait. Additional diagnostic procedures].

In the previous paper published in the Bulletin for Hematology and Blood Transfusion we described the congenital deficit of Hageman factor (HF) with the basic findings. Now we provide addilioval laboratory -diagnostical tests in order to confirm definitively that our patients have the deficit of Factor XII, and not of some other factors of the contact coagulation phase as: Fletcher, Fitzgerald, Williams and Flaujeac. On the other hand, in order to enlight the laboratory-diagnostical problems which one can face in solving of these cases, we have reviewed the basic biochemical characteristics of the contact factors and the mechanism of the beginning of the internal pathway of blood coagulation.