Final answer:
Light blue-topped tubes, containing sodium citrate, are used for activated partial thromboplastin time tests to accurately measure blood clotting time.
Step-by-step explanation:
The color of the tube used for activated partial thromboplastin time (APTT) tests is light blue. The light blue-topped tubes contain sodium citrate, which acts as an anticoagulant by binding calcium in the sample. Because APTT is a test that measures the time it takes for blood to clot while preventing it from clotting too quickly in the tube, the use of sodium citrate is essential for acquiring an accurate measurement.
The color of tube used for activated partial thromboplastin time is light blue. This type of tube is called a sodium citrate tube, and it is used to collect blood samples for coagulation tests. The sodium citrate in the tube prevents the blood from clotting, allowing accurate measurement of clotting time.