There are four types of thrombus, namely: white thrombus, red thrombus, platelet thrombus, microvascular thrombus, mixed thrombus, etc.

1. Thrombus: Also known as gray thrombus, commonly occurs in arteries with rapid blood flow, often related to vascular wall trauma, also known as arterial thrombus. This thrombus is mainly composed of platelets, fibrin, leukocytes, and a small amount of red blood cells. It is gray, rough, curly, striated, hard, and tightly attached to the vascular wall.

2. Thrombus: Also known as a coagulative thrombus, usually occurs in places with slow blood flow or veins, also known as venous thrombus. It is mainly composed of red blood cells, leukocytes, fibrin, and a small amount of platelets. Fresh red thrombus is moist and has certain elasticity, while old red thrombus becomes dry and loses elasticity, which is prone to cause embolism.

3. Platelet thrombus: Commonly seen in microvessels, mainly formed by the aggregation of a large number of platelets, containing a small amount of fibrin. The platelets around the aggregates are prone to release reactions and particle loss.

4. Microvascular thrombus: Commonly seen in precapillary, small arteries, and small veins, and can only be seen under a microscope, hence also known as microthrombus. It is mainly composed of fibrin-ovum white and its monomers, containing an unequal number of platelets, leukocytes, and a small amount of red blood cells. It appears transparent, therefore also known as a hyaline thrombus. This type of thrombus is very common during DIC (diffuse intravascular coagulation).

5. Mixed thrombus: Occurs in arteries, veins, or the chambers of the heart, consisting of three parts: head, body, and tail. The head is a white thrombus, composed of white thrombus and red thrombus, and the tail is composed of thrombus. The head of the thrombus often adheres to the vascular wall, forming a mural thrombus.