Test systems with synthetic peptide substrates in haemostaseology.

Since the early seventies, synthetic peptide substrates have been used in haemostaseology, enabling the introduction of photometry in coagulation analysis. Synthetic peptide substrates are short peptides (3-5 amino acid residues), with a chromogenic group coupled to the C-terminal end by an amide bond. The chromogenic group may be relatively specifically removed by proteases, and measured photometrically. By using the special properties of the many available substrates, test systems have been developed for procoagulant clotting factors, fibrinolytic factors, inhibitors of both systems and also for global tests of plasmatic coagulation. These tests can be performed manually or on automated analytical systems with high specificity, sensitivity and accuracy. The analytical advantages and new possibilities of the tests with chromogenic substrates have, in recent years, decisively stimulated not only haemostaseological basic research, but also clinical investigation and routine. Today, inhibitors of plasma coagulation (e.g. antithrombin III, protein C, C1-esterase inhibitor) as well as fibrinolytic parameters (e.g. tissue plasminogen activator, plasminogen activator inhibitor, alpha 2-antiplasmin) are nearly exclusively determined with chromogenic substrates. Further development will constitute the application of chromogenic substrates to "dry chemistry" methods.