A new aspect of platelet aggregation and a test to measure it.

Blood platelets which aggregate either in vivo or during collection of samples are not taken into account when aggregation is measured on platelet-rich-plasma (PRP). A new test is presented to measure aggregation in whole blood without ignoring these hyperactive platelets. It is based upon the principles that aggregation is arrested when a smear is prepared and that free and aggregated platelets can be counted differentially on smears. The test was carried out on normal individuals, diabetics, patients of myocardial infarction, women on contraceptives, and also on patients of uremia and Glanzmann's disease. It was compared with the tests of Wu and Hoak, Holdrinet and co-workers, and Born. The reproducibility of the parameters measured by this test is better than those measured by the other tests. The test appears to measure a new dimension of platelet aggregation.