The evaluation of the two-stage prothrombin assay

It is shown that (and why) the traditional ways of evaluating a thrombin generation curve do not give acceptable estimations of the prothrombin content of the sample. An alternative method is shown to meet the requirements better; it consists of drawing the thrombin generation curve on a semi-logarithmic graph, and extrapolating the descending slope to zero time. This gives a thrombin concentration representing the prothrombin concentration of the original sample