Bleeding Time

Bleeding Time (BhitungrizeH), a concept introduced into diagnosis in 1910 by the American Duke, is defined as the duration of bleeding from a puncture of the earlobe (or the pulp of the terminal phalanx of a finger) made with a Frank needle (or an analogous instrument); the depth of the puncture, as Duke showed, does not play a significant role; the protruding drops of blood are removed with a strip of filter paper every 1/4 minute. The time is counted from the moment the first drop appears until the bleeding stops. If after the puncture no blood at all shows from the wound, a slight pressure can be applied to the pulp of the finger to cause the first drop to appear, but the following drops must appear without any pressure. In the norm, the B. t. equals 1 min.-2 min.-3 min., in pathological cases it is prolonged (sometimes up to several hours). Sometimes the B. t. varies depending on the site of the puncture. Prolonged B. t. is observed, mainly, in Werlhof's disease, as well as in a number of diseases accompanied by secondary thrombocytopenia (see Werlhof's disease). The diagnostic value of the symptom is relatively small; what is certainly interesting is the dissociation between the coagulability of the blood and the magnitude of the B. t., namely: in Werlhof's disease, the B. t. is prolonged, coagulability is usually normal; in hemophilia, on the contrary, the B. t. is normal, and coagulability is reduced. The B. t. is usually prolonged in proportion to the decrease in the amount of platelets in the blood, but the prolongation of the B. t. apparently does not depend on thrombocytopenia, since a normal B. t. is often observed in the presence of thrombocytopenia, and vice versa. There is a basis for assuming that the B. t. depends on the corresponding functional capacity of the vascular (capillary) endothelium.