Detection of the prethrombotic state due to procoagulant imbalance.

We have reviewed the laboratory methods used to diagnose the prethrombotic state, defined as a procoagulant imbalance between the production and inhibition of enzyme activity in the coagulation pathway short of fibrin deposition. One diagnostic approach is that of measuring the plasma levels of activation peptides which are released from the zymogens of the coagulation cascade when they are activated. Another approach is that of measuring the plasma levels of complexes formed in plasma when enzymes of the coagulation cascade are neutralized by their naturally-occurring inhibitors such as thrombin-antithrombin complex. The clinical usefulness of these methods still needs to be defined with prospective studies.