Thromb Haemost 1990; 64(03): 353-357
DOI: 10.1055/s-0038-1647317
Original Article
Schattauer GmbH Stuttgart

Prediction of Vitamin K Response Using the Echis Time and Echis-Prothrombin Time Ratio

C Solano
The Haematology Department, Princess Alexandra Hospital, Brisbane, Queensland, Australia
,
R G Cobcroft
The Haematology Department, Princess Alexandra Hospital, Brisbane, Queensland, Australia
,
D C Scott
The Haematology Department, Princess Alexandra Hospital, Brisbane, Queensland, Australia
› Author Affiliations
Further Information

Publication History

Received 13 February 1990

Accepted after revision08 June 1990

Publication Date:
04 September 2018 (online)

Summary

Echis carinatus venom contains proteases capable of activating both normal and descarboxy prothrombin. We showed this venom (Sigma) principally activates prothrombin with almost no factor X activation. Echis time in combination with prothrombin time can predict vitamin K responsiveness since the Echis time is usually normal in the presence of descarboxy prothrombin associated with vitamin K deficiency.

38 patients with abnormal routine prothrombin times (PT) had both coagulant and immunogenic factor II assays along with Echis times done before and after vitamin K. Of 22 patients responding to vitamin K, based on correction of PT, 21 had normal initial Echis times and of 16 not responding, 11 had abnormal Echis times, giving a sensitivity of 95.4% and specificity of 68.8% for vitamin K responsiveness. 90% of patients with a PT/Echis time ratio <1.3 and a prolonged Echis time did not correct their PTs with vitamin K therapy.

The 5 non-responders with normal Echis times all showed normal initial coagulant and antigenic prothrombin, but 3 had low F V and/or F VII.