The normal value of platelets is10-300,000.
clotting time
Generally, in the routine examination of medical blood, the examination of coagulation time should be involved.
Measurement of bleeding time of 1. and its clinical significance
Blood flows from a broken or injured blood vessel to a platelet embolus, forming a temporary hemostasis process, which is called hemostasis. Many pathological factors can affect this process and lead to bleeding. Therefore, many experiments have been designed to find the pathophysiological reasons, such as the determination of endothelin, von Willebrand factor (vWF) and platelet aggregation test. These tests are sensitive, but the operation is complicated, and the bleeding time test is often used as the screening test first. If the result is positive, perform the above test again. There are three methods to measure bleeding time, namely Duke method, Ivey method and bleeding time tester method. Duke method is simple to operate, but it is difficult to standardize the depth and width of puncture, and the sensitivity of the experiment is very poor because of the distribution of capillaries and the degree of vasoconstriction at the puncture site. According to the literature, the positive rate of patients with platelets below 3× 109/L is only 4.2. The positive rate of patients with hereditary hemophilia (VWD) was 32%, while the positive rates of test method were 92% and 67% respectively. Although IVY method is more sensitive than Duke method, its operation is complicated, its damage is great, and it is difficult to standardize and popularize the incision. The bleeding time setter method is easy to control, standardized and has high sensitivity, because the blade is embedded in the instrument and is quickly ejected by the spring. Therefore,
Determination of coagulation time and its clinical significance
Coagulation time test refers to the time it takes to draw blood from blood vessels and put it in a test tube from a liquid sol state to a semi-solid gel state. In fact, after the factors reflecting blood (or plasma) are activated, the coagulation factors in the zymogen state in plasma are activated in turn, constantly "amplified", and finally fibrinogen becomes fibrin. The latter forms a reticular network of platelet embolus and red blood cells, and finally the reticular fibrin contracts. Form a hard blood clot. This process requires the participation of coagulation factors such as ⅶ, ⅶ, ⅶ, ⅶ, Ca2+, prothrombin, fibrinogen, etc. The lack of any one of these factors will cause the obstacle of the above-mentioned "continuous amplification" process and lead to poor coagulation. Therefore, prolonged coagulation time can reflect the lack of the above factors. There are roughly six methods to measure solidification time in the experiment. Wang Hongli et al. measured the coagulation time (factor VIII activity) of 12 patients with severe hemophilia by six methods.