Thromb Haemost 1981; 45(03): 237-241
DOI: 10.1055/s-0038-1650178
Original Article
Schattauer GmbH Stuttgart

The Inhibitor of Prothrombin Conversion in Plasma of Patients on Oral Anticoagulant Treatment

R M Bertina
The Haemostasis and Thrombosis Research Unit, Leiden University Hospital, Leiden, The Netherlands
,
M E J Westhoek-Kuipers
The Haemostasis and Thrombosis Research Unit, Leiden University Hospital, Leiden, The Netherlands
,
G H J Alderkamp
The Haemostasis and Thrombosis Research Unit, Leiden University Hospital, Leiden, The Netherlands
› Author Affiliations
Further Information

Publication History

Received 13 January 1981

Accepted 20 March 1980

Publication Date:
06 July 2018 (online)

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Summary

Pooled plasma of patients under stable oral anticoagulation has been analysed with respect to the presence of the vitamin-K dependent factors (factors II, VII, IX and X). Of all factors 1.5-2 times more antigen than procoagulant activity was present. The concentration of factors II, X (measured spectrophotometrically) and VII is about 0.25 U/ml while factor IX is slightly higher. Coagulation assays of factor X always gave lower values than the spectrophotometric assay. This discrepancy was not influenced by the removal of either factor II-factor VII- or factor IX antigen. However, when the factor X antigen was replaced by normal factor X, all factor X assays gave identical results, indicating that PIVKA X is responsible for these discrepancies. Using the technic of the Thrombotest-dilution curve it was shown that PIVKA X is the factor that causes the abnormal prolongation of ox-brain prothrombin time in these plasmas.