Abstract: An apparatus and method for performing a coagulation time test on a sample of blood wherein the blood is deposited in a fluid reservoir and disposable cuvette. Within the cuvette is formed a capillary conduit have at least one restricted region. The cuvette is inserted into a testing machine which engages the cuvette and draws blood from the fluid reservoir into the capillary conduit. The blood is then caused to reciprocally move within the capillary conduit whereby the blood is forced to traverse the restricted region. The testing machine measures the time required each time the blood is caused to traverse the restricted region. When a measured time is a predetermined percentage longer than an immediately preceding time, coagulation is considered to have occurred and the overall coagulation time is displayed to the operator.