What are the colors of the test tubes used by a phlebotomist and what tests are each color used for?

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kdburgess eNotes educator| Certified Educator

With over a million tests performed, this would be a difficuult inclusive answer. In general, there are numerous tubes (approxiamtely 20); however, the most common tubes are lavender, green, gray, "tiger", yellow, red, pink, navy, lt blue, and lt green.

The lavender is generally used for hematology tests such as a CBC and contains EDTA. This is an anticoagulant that chelates calcium. It can be used for come chemistry tests such as glycohemoglobin and ammonia tests.

The green tube contains either sodium or lithium heparin (more commonly lithium heparin) and are used for stat chemistry tests. The additive is an anticoagulant that yields plasma, a perfect choice for stat chemistry tests. The lt green is similar; however, it contains a gel barrier that separates the plasma from the cells.

The gray tube is generally used for chemistry tests such as blood alcohol or glucose tolerance tests. The additive, either potassium oxalate or sodium flouride, is a preservative that is to preserve the function of the analyte. In glucose testing, it serves as a glycolytic, in alcohol testing, it preserves the "content of alcohol" as it was at the time it was drawn.

The "tiger top" or yellow tube contains a clot activator and gel barrier known as thixotropic gel. This prevents cellular contamination when centrifuged and keeps the serum from combining with cells. This is used for all general chemistry tests such as cardiac panels, BMP, CMP, Thyroid, Iron studies, etc...

The pink top is generally a blood bank tube and contains the same as the lavender, EDTA. The main difference is that one is a 4.5 ml draw and the other an 8-10 ml draw tube.

The lt blue tube is used to perform coagulation studies. This is generally a PT, PTT, fibrinogen and maybe a D-dimer. It contains sodium citrate.