The inner wall of the blood collection tube is uniformly sprayed with heparin sodium or lithium heparin, which can quickly act on blood samples, so that high-quality plasma can be quickly obtained.

In addition to the characteristics of heparin sodium, lithium heparin also has no interference with all ions including sodium ions, so it can also be used for the detection of trace elements.

Heparin is a type of mucopolysaccharide with sulfate groups and strong negative charges. It facilitates antithrombin lll to deactivate serine endopeptidase and therefore, prevents the formation of thrombin. It also prevents blood platelets from aggregating. Heparin tubes are normally used for biochemistry tests in emergency setting and tests in blood flow. Heparin tubes are also the best choice for electrolytes testing. When testing for sodium in blood samples, heparin sodium cannot be used because of that is may impact the results. In addition, heparin tubes cannot be used for white blood cell counting and sorting due to that heparin induces white blood cell aggregation.