Bedside monitoring of warfarin therapy by a whole blood capillary coagulation monitor.
A recently developed portable capillary coagulation monitor device allows rapid determination of prothrombin time (PT) in sec. and in International Normalized Ratio (INR) from a drop of whole blood. Considering a possible application of this device for monitoring of warfarin therapy at bedside or at outpatient clinic, a comparative study was performed in patients receiving warfarin between the whole blood capillary PT(WBC-PT) and conventional laboratory tests such as plasma PT (LAB-PT) and Thrombotest (TTO). There was an excellent positive correlation (r = 0.95, n = 49) between LAB-PT(sec) and WBC-PT(sec). As the correlation coefficient between WBC-PT(sec) and the reciprocal of LAB-PT(%) was excellent (r = 0.95, n = 49), it is feasible to convert WBC-PT(sec) to LAB-PT(%) by the following formula; y = 313.48x +8.29 (x:reciprocal value of LAB-PT(%), y:WBC-PT). As the correlation between WBC-PT(sec) and TTO(sec) was also excellent (r = 0.85, n = 63), TTO(%) may be likewise estimated by the following formula; y = 66.49x + 11.36 (x:reciprocal value of TTO(%), y:WBC-PT). From these observations it is concluded that the determination of WBC-PT is simple and accurate and that the monitoring of warfarin therapy is easily performed by the present method.
Yano
Y
Y
Department of Surgery II, Osaka University Medical School, Japan.
Kambayashi
J
J
Murata
K
K
Shiba
E
E
Sakon
M
M
Kawasaki
T
T
Mori
T
T
D000556:Ambulatory Surgical Procedures; D001780:Blood Coagulation Tests / Q000295:instrumentation*; D006470:Hemorrhage / Q000517:prevention & control; D006801:Humans; D007834:Lasers; D010783:Photometry / Q000295:instrumentation; D011182:Postoperative Care; D011517:Prothrombin Time; D014656:Vascular Surgical Procedures; D014859:Warfarin / Q000009:adverse effects / Q000097:blood* / Q000493:pharmacokinetics
D014859:Warfarin