Which of the following additives is present in the green tube top?

The green tube top is primarily associated with the presence of sodium heparin and lithium heparin. These are anticoagulants used in various laboratory tests to prevent the coagulation of blood. Sodium heparin and lithium heparin work by inhibiting thrombin formation and are commonly used in tests that require plasma samples. This makes the green tube suitable for tests such as chemistry panels and other plasma-based analyses.

In contrast, other tube tops have different color codes and contain specific additives for separate functions. For instance, sodium citrate found in light blue tops is usually for coagulation tests, while EDTA and K2EDTA, found in lavender or purple tops, are used for hematology tests by binding calcium. Therefore, the correct identification of the green tube top with sodium heparin and lithium heparin is essential for ensuring proper sample collection and accurate lab results.