What is Blood Coagulation and How Does It Work?

When we undergo routine physical examinations, we are often required to have blood coagulation tests. The term "blood coagulation" is frequently heard in our daily lives, but most people do not have a deep understanding of it. Blood coagulation reflects an individual's clotting response, and any abnormalities in coagulation can lead to uncontrollable bleeding in case of bodily injuries. Therefore, it is crucial to understand blood coagulation, especially when undergoing surgical procedures where coagulation tests are routinely performed.

1. What is Blood Coagulation?

Blood coagulation, also known as blood clotting, refers to the ability of human blood to transition from a liquid state to a solid state. It is a vital physiological function that helps the body stop bleeding. When coagulation is compromised, patients may experience significant bleeding symptoms, such as those seen in hemophiliacs who have difficulty stopping bleeding after injuries due to coagulation disorders.

Blood coagulation is achieved through a series of amplified reactions involving various coagulation factors.

2. What Are the Four Components of Blood Coagulation?

The four main components of blood coagulation are hypercoagulability, coagulation, bleeding, and hemostasis. These are the most commonly encountered clinical situations related to coagulation. Understanding the coagulation status is crucial for screening and diagnosing bleeding disorders, assessing pre-thrombotic states and thrombotic diseases, as well as guiding the proper use and prognostic estimation of anticoagulant medications. The four coagulation tests help doctors accurately assess these issues.

3. Considerations for Blood Coagulation Tests

3.1 Blood Collection:

• Prevent tissue damage and avoid the introduction of exogenous factors.
• Submit samples for testing as soon as possible.
• Avoid collecting blood from infusion lines to prevent dilution and contamination with medications.
• The pressure and duration of blood drawing can affect local blood concentration, which can, in turn, impact platelet release and the activity of certain coagulation factors.

3.2 Collection Tubes: Plastic or polyethylene tubes are preferred.

3.3 Anticoagulants:

• 3.8% Sodium Citrate is recommended as it effectively prevents the degradation of coagulation factors V and VIII.
• The ratio of anticoagulant to blood should be 1:9.

3.4 Plasma Preservation: Plasma samples should be processed immediately or stored in a refrigerator (2-8°C). Plastic tubes have the least impact on sample quality.