Coagulation testing has evolved from the use of the manual tilt-tube clotting time in the early 1900's to the use of molecular diagnostics today. Over the years, the measurement of a clot endpoint has been the basis of testing. Automated instruments have replaced the manual visual methods and allowed for precise measurements of the clot endpoint. In addition, immuno-logic and chromogenic methodology has also been adapted into the coagulation laboratory, therefore providing an additional antigenic and enzymatic perspective. Today, most modern automated coagulation instruments offer a single test platform that incorporates optic, immunologic, and chromogenic methods. The arrival of molecular diagnostics now adds another dimension for the evaluation of hemostatic defects.

Historically, coagulation testing was confined mostly to the screening or work-up of patients with bleeding disorders. The availability of routine laboratory tests for patients with thrombosis has slowly increased over the years and the demand for this testing continues to grow. Molecular diagnostics has found an important role in this area of coagulation disorders. DNA-based tests are available for detection of the Factor V Leiden mutation, the Prothrombin 20120A mutation, and the methyl-enetetrahydrofolate reductase mutation.

At the same time, the significance of molecular testing for coagulation defects associated with thrombosis and the impact on patient care continues to be controversial. Physicians from different specialties are struggling with the questions surrounding the availability of a larger test "menu": whom, when, and what to test? (1). Given the tendency to practice predictive medicine and the resulting increased screening of specific subgroups of patients for specific genetic information, it is anticipated that the role of molecular diagnostics for coagulation disorders will continue to increase with time (2).

In this chapter, a brief review of the procoagulant and anticoagulant systems will be followed by a general description of the molecular defects underlying various coagulation disorders. This, in turn, will provide a background for a review on the molecular genetic testing available in coagulation, particularly for the hereditary hypercoagulable states. Finally, the clinical significance of testing for Factor V Leiden, Prothrombin G20210A, and the methylenetetrahydrofolate reductase mutations will be discussed.

Pregnancy Guide

Pregnancy Guide

A Beginner's Guide to Healthy Pregnancy. If you suspect, or know, that you are pregnant, we ho pe you have already visited your doctor. Presuming that you have confirmed your suspicions and that this is your first child, or that you wish to take better care of yourself d uring pregnancy than you did during your other pregnancies; you have come to the right place.

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