TY - JOUR T1 - Control of anticoagulant therapy: Progress and problems blems AU - QUICK AJ Y1 - 1963/02/01 N1 - 10.1001/archinte.1963.03620260094017 JO - Archives of Internal Medicine SP - 234 EP - 239 VL - 111 IS - 2 N2 - The one-stage prothrombin time was intimately associated with the development of oral anticoagulant therapy. As Link has stated: "Through it the hemorrhagic agent of spoiled sweet clover hay was laid out on the table in pure crystalline form." Furthermore, without this simple test, the introduction of bishydroxycoumarin (Dicumarol) into therapy would have been exceedingly hazardous. In the early studies,1 the increased prothrombin time was regarded as a depression solely of prothrombin, and this assumption was supported by the finding that the 2-stage method of Warner, Brinkhous, and Smith2 likewise showed a marked decrease of prothrombin when bishydroxycoumarin was given. The discoveries of Factor V (labile factor) in 1943,3 and of a serum agent (Factor VII) a few years later,4,5 made it evident that neither method measured prothrombin specifically. It was the one-stage test, however, which has received most of the criticism and been subjected to numerous SN - 0003-9926 M3 - doi: 10.1001/archinte.1963.03620260094017 UR - http://dx.doi.org/10.1001/archinte.1963.03620260094017 ER -