High levels of fibrinogen and D-dimer reflect a hypercoagulable state of the blood and require vigilance against thrombotic disorders such as pulmonary embolism and bilateral lower extremity venous embolism. 1. D-dimer is a degradation product of fibrinogen, which reflects the coagulation function of the blood. Elevated levels of both reflect a hypercoagulable state of the blood and a higher risk of thrombotic diseases. 2. High levels of fibrinogen and D-dimer can be seen in the following thrombotic diseases. (1) Pulmonary embolism: in addition to high fibrinogen and D-dimer, it may be accompanied by symptoms such as chest tightness, chest pain, dyspnea, etc. Chest high-resolution CT and other examinations can clarify the diagnosis. (2) Double lower extremity venous embolism: in addition to high fibrinogen and D-dimer, it can be accompanied by lower extremity edema, pain, numbness and other symptoms, limb venous ultrasonography and other examinations can assist in the definitive diagnosis. Fibrinogen and D-dimer high suggest timely consultation, clear diagnosis, early treatment.