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A Practical Guide to Laboratory Haemostasis

 

Taipan Venom Time



Introduction

The Taipan venom time employs a reagent isolated from the venom of the Taipan snake (Oxyuranus scutellatus) that directly activates prothrombin in the presence of phospholipid and calcium.


Principles

The Taipan venom from Oxyuranus scutellatus contains at least one prothrombin activator with can convert prothrombin to thrombin in the presence of phospholipid and calcium.

Method

The test involves diluting a reference phospholipid preparation so that the concentration of phospholipid [PL] is limited. The diluted PL is then mixed and incubated at 37°C with normal or test plasma plus Taipan snake venom diluted with 0.025M calcium chloride. The time taken to clot formation is recorded and the test is then repeated using a platelet neutralisation procedure in which washed lysed platelets are substituted for the PL. The ratio of test and control clotting times is calculated and a positive test for LA is defined as a ratio of ≥1.1 with correction to ≤ 1.1 or by >10% with lysed platelets.

Interpretation & Reference Ranges

The ratio of test and control clotting times is calculated and a positive test for LA is defined as a ratio of ≥1.1 with correction to ≤1.1 or by >10% with lysed platelets.

Data Interpretation

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