Which color tube is recommended for the collection of blood for coagulation studies?

The light blue top tube is specifically designed for coagulation studies because it contains sodium citrate, an anticoagulant that preserves the blood's clotting factors and allows for accurate testing of coagulation parameters. This tube has a specific blood-to-additive ratio of 9:1, which is crucial for obtaining reliable results in tests such as PT (prothrombin time) and aPTT (activated partial thromboplastin time). The proper collection technique using the light blue top tube helps prevent clotting, ensuring that the specimen reflects the true hemostatic function of the blood.

In contrast, the other tubes do not contain the appropriate additive needed for coagulation studies. The green top tube contains heparin, which can interfere with coagulation tests. The gray top tube contains fluoride or oxalate, which is used mainly for glucose and lactate studies. The red top tube is often used for serum tests and does not contain any anticoagulants, making it unsuitable for coagulation assessments. Thus, the use of a light blue top tube is essential for achieving accurate coagulation test results.