The Ground-Glass Clotting Time

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A screening test should be simple to perform, give few false-negative results, and be little affected by factors other than those being tested. The whole-blood clotting tests currently in general use do not meet these criteria. While these tests detect most severe defects in blood coagulation, they are often normal in the presence of moderate or mild deficiencies. Thus, patients with mild hemorrhagic disorders may not be recognized from these tests, and yet during a surgical operation or after accidental injury serious bleeding may occur. Furthermore, the whole-blood clotting tests are too insensitive to be of value in monitoring the results of replacement therapy in, for instance, a patient with hemophilia. A quick, reliable, and sensitive test is needed.

Since 1959 we have been using a test in which increased surface activation of the coagulation mechanism is achieved by the addition of fragments of glass. We have called this test the ground-glass clotting time. It is extremely simple to perform, can be carried out quickly at the bedside and is little affected by variations in technic. Furthermore, it has proved to be much more sensitive than the Lee and White1 clotting test and slightly more sensitive than the partial thromboplastin time (PTT).2

This report evaluates the ground-glass clotting time (GGCT) as a screening test for hemorrhagic disorders and as a monitor for coagulant and anticoagulant therapy.

Materials and Methods

The particles of glass used for the ground-glass clotting time are obtained by crushing discarded glassware using a mortar and pestle.



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