Evaluation of a Photoelectric Clot Timer for the Performance of Prothrombin Times

This report consists of an evaluation of a commercially available photoelectric clot timer which can be used for performing prothrombin times. In the last two years, approximately 40,000 determinations have been satisfactorily performed with this apparatus. In addition, with the use of the timer, we have been able to pick up unsuspected fibrinogen deficiencies during the course of the performance of routine prothrombin times.