tourniquet test, a test of capillary fragility, caused by an abnormality in the capillary wall or thrombocytopenia, in which a blood pressure cuff is applied for 5 minutes to a person’s arm and inflated to a pressure halfway between the diastolic and systolic blood pressure. The number of petechiae within a circumscribed area of the skin may be counted, or the results may be reported in a range from negative (no petechiae) to +4 positive (confluent petechiae).
