bleeding time

Under certain conditions, the time required for humans to puncture the skin's capillaries from the natural flow of blood to the natural stop is called bleeding time (BT). BT is affected by the number and quality of platelets, capillary structure and function, and the interaction between platelets and capillaries, but is less affected by blood coagulation factor content and activity. The BT assay has the Duke method and the Ivy method, and it is currently recommended to use a standardized bleeding time method (TBT). Basic Information Specialist classification: growth and development examination classification: blood examination Applicable gender: whether men and women apply fasting: not fasting Analysis results: Below normal: Shortened bleeding times are seen in some severe hypercoagulable states and thrombosis. Normal value: Duke method: 0.5-6min IVY method: 2-7min Bleeding time tester method: 2.3-9.5min Above normal: Prolonged bleeding time is seen in abnormal platelet counts such as thrombocytopenia and thrombocytopenia. negative: Positive: Tips: Patients with coagulopathy such as hemophilia are not suitable for this test. Normal value Duke method: 0.5 to 6 minutes. IVY method 2 ~ 7min. The bleeding time measuring method was 2.3 to 9.5 min. The 2h bleeding time after taking the aspirin tolerance test was abnormal for 2 minutes before taking the drug. Clinical significance This project is mainly used to check for platelet diseases, defects in function between blood vessels and platelets, and defects in certain coagulation factors. 1. The bleeding time is extended in: a. Abnormal platelet counts, such as thrombocytopenia and thrombocytopenia. b. Platelet quality defects such as congenital and acquired platelet diseases. c. Certain clotting factor deficiency, such as von Willebrand disease, low (no) fibrinogenemia, and disseminated intravascular coagulation. d. vascular diseases, such as hereditary telangiectasia. e. Drug effects, such as taking dipyridamole, acetylsalicylic acid, etc. 2. Shortening of bleeding time is seen in some severe hypercoagulable states and thrombosis. High results may be diseases: neonatal purpura, rift fever, pediatric hemorrhagic disease, crush syndrome, thrombocytopenia, hemophilia A, neonatal hemolytic disease, secondary thrombocytosis in children, immunity in the elderly Thrombocytopenic purpura, pediatric idiopathic thrombocytopenic purpura Inappropriate people: People with coagulopathy such as hemophilia. Inspection process (1) Influencing factors of BT measurement include: skin incision depth, length, position, direction, pressure on capillaries; skin temperature. Among them, the most important factor is the depth of the incision. For children, the elderly, and patients with a history of scar formation, blood counts can be determined by measuring the TBT instead of TBT. The BT analyzer method is reliable and repeatable. And according to the needs, different types of measuring instruments can be used for standard incisions of different lengths and depths, suitable for patients of different ages. The Duke method is simple and easy to use, especially for preoperative hemorrhage screening. However, because the earlobe is susceptible to external temperature and blood flow distribution, and the puncture depth and blood flow velocity are difficult to control, the reliability is poor. (2) Blood collection (artificial trauma): need to pay attention to keep warm, especially in winter, otherwise it will affect the results. The length and depth of the puncture wounds of the Ivy method and the Duke method should be well mastered. Avoid result errors. (3) Puncture position: Choose to avoid superficial veins, scars and diseased skin. (4) The length of the blade of the first two methods is parallel to the forearm to ensure that the wound is consistent with the nerves and blood vessels. There are two kinds of incisions in the forearm by the measuring method: the horizontal incision perpendicular to the forearm of the blade and the vertical incision parallel to the forearm; the high sensitivity of the horizontal incision is the preferred method, but it is suitable for infants under 4 months. Vertical incision to avoid scar formation. (5) When the filter paper absorbs blood, avoid contact with the wound, and can not squeeze the wound. (6) Patients should avoid taking drugs that affect blood vessel walls and platelets before testing, such as aspirin. However, if oral aspirin is measured, the BT is measured before and 2, 4 hours after taking the drug, and the change is observed, that is, the aspirin tolerance test is more sensitive than BT. If the BT is normal, the test may be positive. Not suitable for the crowd Have a coagulopathy such as hemophilia. Adverse reactions and risks May cause bleeding.