There are five indicators commonly used in clinical monitoring of coagulation: 1. activated partial thromboplastin time, normal value is 32-43 seconds, more than 10 seconds longer than the normal control value is abnormal. The activated partial thromboplastin time is used for screening tests of the endogenous coagulation system and is also the preferred indicator for monitoring heparin. 2. plasma fibrinogen measurement, the normal reference range is 2-4 g/L. If plasma fibrinogen is elevated, it can be seen in pre-thrombotic or hypercoagulable states. 3. plasma prothrombin time, the normal value is 11-13 seconds. Patients measured quality more than 3 seconds above the normal control value is abnormal, mainly in response to exogenous coagulation system each coagulation factor total coagulation status of the screening test. 4, international standardized ratio, normal value of 1.0 plus or minus 0.1, mainly used to monitor the indicators of oral anticoagulants. 5, plasma prothrombin time, normal value of 16-18 seconds, more than 3 seconds above the normal control value is abnormal, mainly is an indicator for monitoring fibrinolytic activity.