What is the purpose of using a light blue top tube?

The light blue top tube is specifically designed for coagulation tests. This tube contains sodium citrate, which is an anticoagulant that works by binding calcium ions in the blood, thus preventing clotting. This is crucial for accurate coagulation testing, as it preserves the plasma in its natural state and allows for precise measurement of clotting factors. Tests commonly performed in this tube include prothrombin time (PT) and activated partial thromboplastin time (aPTT), which are vital for assessing bleeding disorders and monitoring anticoagulant therapy.

Using a light blue tube for other types of tests, such as blood cultures, chemistry panels, or hematology tests, would not yield accurate results. Blood cultures require a sterile container to detect microbial growth, chemistry profiles generally require serum rather than plasma, and hematology tests are typically conducted using lavender or pink top tubes that contain EDTA as an anticoagulant. Thus, the importance of using the light blue top tube specifically for coagulation tests is due to its unique composition that ensures the integrity of the sample for these evaluations.