Clinical evaluation of a fully automated chromogenic method for prothrombin time compared with a conventional coagulation method.

The clinical usefulness of a chromogenic method for prothrombin time (PT) determination has been assessed in a wide range of clinical conditions, and it is compared with the conventional clotting method for PT. The new method appears to be as sensitive as the clotting PT to deficiencies of clotting factors of the extrinsic and common pathway, except for fibrinogen. Patients with proven liver disease were correctly diagnosed with a prevalence of abnormal results comparable to that by the clotting PT. Results by the two methods correlated highly (r = 0.96) for normal and congenitally deficient plasmas as well as for plasmas from patients on oral anticoagulant treatment (r = 0.95). High reproducibility (between-assay CV less than 3%) and easy adaptation to centrifugal analyzers make it a suitable candidate to replace the conventional method.