Heparin test tubes have a ____ top.

Heparin is an anticoagulant that is commonly used in various laboratory tests to prevent the clotting of blood samples. The correct color associated with heparin test tubes is green. This is due to the inclusion of heparin as an additive, which helps to achieve the desired anticoagulant effect during blood collection and analysis.

The green top tubes usually contain either sodium heparin or lithium heparin, which are the forms of heparin used. These tubes are particularly useful in tests that require plasma, as they allow for the rapid separation of plasma from blood cells after centrifugation without the formation of clots. Therefore, selecting green top tubes ensures proper sample integrity for tests that are sensitive to anticoagulation, making them crucial in the field of veterinary pharmacology and other medical practices.