The four coagulation labs include prothrombin time (PT), activated partial thromboplastin time (APTT), prothrombin time (TT) and fibrinogen (FIB). 1. Prothrombin Time (PT): mainly reflects exogenous coagulation, reference interval: 11-13 seconds, if the test result exceeds the normal control value by more than 3 seconds, it is abnormal. 2. Activated partial thromboplastin time (APTT): mainly reflects endogenous coagulation, and is also the preferred indicator for detecting the dosage of heparin therapy. Automatic coagulation analyzer method: 23-26 seconds, if the test result exceeds the normal control value by more than 10 seconds, it is abnormal. 3. Prothrombin time (TT): mainly coagulation method: 16-18 seconds, if the result of the laboratory test exceeds the normal control value by more than 3 seconds, it is abnormal. 4. Fibrinogen (FIB): reference interval: 2-4g/L. It is recommended that if the results of the four coagulation labs are done, they should be analyzed under the guidance of a physician and treated accordingly as prescribed by the doctor.