A Machine for the Determination of the Whole Blood Clotting Time

Summary

The whole blood clotting time in glass tubes is widely used for the control of heparin therapy. In the investigation of coagulation disorders the whole blood clotting time is commonly done both in glass tubes and in tubes with non-wettable surfaces.

This presentation concerns the development of a portable mechanical device, the Coagulation Timer, to perform this test. The end point is measured automatically by a photo-electric mechanism. Only a few minutes are required to draw blood and place samples in the machine, which may then be left unattended.

Data are presented to show that results obtained using glass tubes in the Coagulation Timer correlate well with those of a technician using a modification of the Lee White method. Further data are presented establishing the normal range for the whole blood clotting time using polystyrene tubes in the Coagulation Timer.