What additive is found in the dark green tube top used for testing?

The dark green tube top is used for tests that require heparin, specifically sodium or lithium heparin as its additive. Heparin is an anticoagulant that helps to prevent the blood from clotting, enabling the collection of plasma for various laboratory tests. This property of heparin is especially important in situations where a rapid response is necessary, such as in certain emergency tests or when a plasma sample is needed for further analysis.

Sodium heparin is more commonly associated with the dark green tube, while lithium heparin can also be used for certain applications, but the primary purpose remains the same—preventing coagulation. This makes the dark green tube a valuable choice in many clinical settings for a variety of tests, including certain chemistry tests.

Other options are associated with different tube colors and additives. Potassium EDTA is used in lavender-top tubes, while buffered sodium citrate is found in light blue-top tubes. The broth mixture is not relevant to blood collection tubes and is typically associated with microbiology or culture applications. Understanding the specific additives and their functions is crucial for proper specimen collection and handling in phlebotomy practices.