It has long been recognized that a state of lowered capillary resistance exists in patients with thrombocytopenic purpura. It has furthermore been recognized that the degree of lessened resistance is in general proportional to the severity of the disease process. Therefore a determination of the state of resistance of the capillaries is generally included among the measures employed to ascertain the presence and the activity of the disease. The three principal methods which have been used in this determination are (1) the tourniquet test, (2) the intradermal venom test and (3) the suction test.
The tourniquet test was introduced as a method of measuring capillary resistance in 1911 by Weill, Rumpel, Leed and others. Despite the recent introduction of qualitative1 and quantitative2 modifications, this type of determination leaves much to be desired, as it is both cumbersome and time consuming. Furthermore, it is poorly adapted to measuring the
ELLIOTT RHE. THE SUCTION TEST FOR CAPILLARY RESISTANCE IN THROMBOCYTOPENIC PURPURA. JAMA. 1938;110(15):1177–1179. doi:10.1001/jama.1938.02790150023008