Which of the following materials is used in the green blood collection tube?

The green blood collection tube typically contains heparin, which is an anticoagulant that prevents blood from clotting. Heparin works by inhibiting the activity of certain clotting factors and is commonly used when immediate plasma or serum testing is required. This tube is often utilized for tests that require whole blood or plasma, such as certain chemistry tests or when immediate processing is necessary for accurate results.

The other materials mentioned, such as serum, EDTA, and citrate, have different applications. Serum is collected from tubes without anticoagulants and is not suitable for green tubes designed with heparin. EDTA, another anticoagulant, is used in purple or lavender-top tubes for hematological tests and does not serve the same function as heparin. Citrate is found in light blue tubes and is primarily used for coagulation studies. Each type of tube is designed to preserve specific characteristics of the blood sample and facilitate a range of laboratory tests.