The Thromboplastinogen^[*)] activity time (TAT) Test

Summary

The thromboplastinogen activity time (TAT) test is described. The method is based on the finding that rabbit brain extract heated to 60° C loses its holo-thromboplastin activity but retains the properties of platelet extract and can, therefore, be used as a substitute for platelet extract in the prothrombin consumption test. The application of the test to differentiate hemophilia from thrombocytopenia and thrombasthenia is illustrated by case reports. The use of the test for the differential diagnosis of hemophilia and PTC deficiency is outlined and examples of its application given.

 

^*) Thromboplastinogen = Factor VIII; as Factor IX was not yet discovered when the term thromboplastinogen was proposed in 1947, the latter applies to Factor IX as well.

• References

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• 6 Quick A. J, and Stefanini M. The state of component A (prothrombin) in human blood; Evidence that it is partly free and partly in an inactive or precursor form. J. Lab. clin. Med. 34: 1203 1949;