What type of specimen is typically collected in the light blue-top tube?

The light blue-top tube is specifically designed for collecting specimens that require the use of sodium citrate as an anticoagulant. This anticoagulant prevents blood from clotting, allowing for the accurate measurement of clotting factors in plasma during coagulation studies. The citrate in the light blue-top tube creates a proper environment to assess the efficacy of the coagulation cascade, making it essential for tests such as prothrombin time (PT) and activated partial thromboplastin time (aPTT).

This type of tube is fundamental in diagnosing clotting disorders and monitoring patients on anticoagulation therapy. The design and function of the light blue-top tube make it unsuitable for other specimen types, such as serology tests, hematology, or capillary blood tests, which utilize different collection methods and additives.