Prothrombin Time in Normal Indians

Dam and his colleagues (1934, 1936) were the first to show the important role of vitamin K in the synthesis of prothrombin in the liver. Numerous studies by Hawkins and Brinkhous (1936), Dam and Glavind (1938), Zuckerman et al. (1939), and Clark et al. (1939) have since established the efficiency of this vitamin in combating certain hsemorrhagic states, characterized by lowered prothrombin levels. It has been particularly effective in obstructive jaundice, hsemorrhagic disease of the newborn, some intestinal disorders, e.g. sprue, celiac disease, and to a limited extent in certain diseases of the liver. The results of several investigations have established that the prothrombin time is fairly constant in normal individuals. Hence the criteria used up to now, for a rational treatment by this vitamin has been the prolongation of prothrombin time. Various methods and modifications have been suggested for the determination of prothrombin time of blood plasma. The simplicity and ready applicability of the procedure suggested by Quick (1938) has resulted in wider adoption of this method for clinical investigations. This technique makes use of thromboplastin prepared from tissue extracts, such as those from brain, liver and lung. These, however, vary in potency and readily deteriorate necessitating frequent checking of results with extracts of known potency. Modifications have therefore been suggested which avoid the use of tissue extracts. The most important of these is that by Fullerton (1940) which makes use of a dilute solution of Russell's viper venom as the source of thromboplastin. The chief advantages of the use of this material are : (1) it is constant in potency; (2) the clear solution obtained permits more easily the detection of the end point than does the turbid one produced by the tissue extract. Fullerton (loc. cit.) studied the normal prothrombin level using this method and found the normal values to range from 18 to 25 seconds. It has been further tested by many workers and found to be quite satisfactory for clinical investigations. Page and Russell (1941) carried out a comparative study of the two methods on seventy-two cases and found them to give concordant results. The average values reported by these workers are : Quick's method 25; Fullerton's method 24.7. In India comparatively few studies have been made to determine the normal prothrombin time in Indian subjects and its variation under diseased states. Reddy and Venkataramiah (1941) have studied the prothrombin time of 20 healthy adults using Illingworth's (1939) modification of Quick's method, and find the values ranging from 15 to 20 seconds. Iyengar et al. (1942) as a result of a comparative study of their modified method and Fullerton's technique, on 25 cases, report the average value for normal prothrombin time as 9 and 12 seconds respectively. Rahman and Giri (1945) utilizing the technique of Fullerton as modified by Iyengar et al. (loc. cit.) determined the prothrombin time of 17 healthy adults and their values ranged from 18 to 13 seconds.