Wet gangrene of the lower extremities is a typical manifestation of venous thrombosis of the lower extremities, where the tissue necrosis is followed by specific morphological changes such as black and dark green due to infection by secondary spoilage bacteria and other factors, called gangrene. So how do you check for wet gangrene of the lower extremities? Here’s what you need to know. Laboratory tests: radioactive fibrinogen test: the application of 125I-labeled human fibrinogen can be absorbed by fresh blood clots, so after blocking the iodine absorption function of the thyroid gland, intravenous injection of the agent to scan both lower extremities, such as the observation of radiotracer plunge or set plunge, it will help to diagnose. Other auxiliary examinations: 1.Nuclidean venography: injecting nuclide labeled 99mTc (99mTc) human albumin particles from the dorsal veins of both feet for venous imaging to observe the venous imaging of calf, thigh, pelvis and abdomen, and the “hot spot” indicates where the fresh thrombus is located. 2.Doppler flow and volume tracer examination: It is a non-invasive examination method, which can help to clarify the blood return and blood supply condition of the affected limb. 3.Venogram: It can directly visualize the veins and determine the presence of thrombus, its scope, shape and the condition of collateral circulation. It not only helps to decide the diagnosis, but also helps to observe the result of treatment directly. Although this method is the most reliable, it is not necessary to complete this test when the disease is too serious. It is also necessary to consider that the contrast itself may aggravate the lesion, and generally inject a small amount of heparin into the contrast area after the contrast agent is injected, which helps to prevent the aggravation of the lesion. 4. Measurement of venous pressure: It helps to understand the condition and observe the development. It can be measured alone or at the time of imaging. Complications: Thromboembolism (pulmonary embolism, cerebral embolism, etc.) may occur; chronic ulceration of the lower limbs, etc. In severe cases, acute pulmonary embolism may occur and lead to sudden death. Therefore, it is recommended that patients should pay high attention to active treatment to avoid more serious consequences.