Abstract: Methods and techniques are described for detecting the presence of cancer procoagulant activity in blood serum. The method provides a means of distinguishing persons or animals having cancer from those who do not have cancer. The method involves techniques for processing serum such that the activity of cancer procoagulant can be measured while the activity of other coagulation enzymes in the serum is minimized or eliminated. Then the serum can be analyzed for cancer procoagulant activity.