Red-top tube: Contains no anticoagulant or preservative.
Use: Serum or clotted whole blood. Serum must be separated from cells within 45 minutes to two hours depending on the test
Lavender-top tube: Contains K2 EDTA.
Use: EDTA whole blood or plasma. Separate and send plasma in a plastic transport tube labeled “Plasma, EDTA.” Send whole blood in a lavender-top tube.
Gray-top tube: Contains sodium fluoride (a preservative) and potassium oxalate (an anticoagulant).
Use: Sodium fluoride whole blood or plasma. Send plasma in a plastic transport tube labeled “Plasma, Sodium Fluoride.” Send whole blood in a gray-top tube.
Blue-top tube (also light blue-top tube): Contains sodium citrate. Be sure to use only tubes with a 3.2% sodium citrate concentration. These are easily identified by the yellow diagonal stripes on the label.
Use: Sodium citrate plasma. Send plasma in a plastic transport tube labeled “Plasma, Sodium Citrate.” Send whole blood in a blue-top tube.
Green-top tube: Contains sodium heparin or lithium heparin.
Use: Heparinized whole blood or plasma. Send plasma in a plastic transport tube labeled “Plasma, Sodium Heparin” or “Plasma, Lithium Heparin.” Send whole blood in a green-top tube.
Yellow-top tube: Contains acid citrate dextrose (ACD) solution.
Use: ACD whole blood. Send whole blood in a yellow-top tube.
Royal blue-top tube: Contains sodium EDTA for trace metal studies. Some royal blue-top tubes do not contain EDTA.
Use: EDTA whole blood or plasma. Send whole blood in a royal blue-top tube.
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