Capped sterile tubes with an internal vacuum that are commonly used to collect venous blood specimens; products are available in various materials, with various stopper types, and anticoagulants.

Evacuated blood tubes are sealed, single-use, capped tubes used with suitable collection needles and tubing for the safe and sterile collection of blood samples from human or animal subjects. They are partially evacuated to facilitate blood draw when the collection needle punctures the cap. The closure caps may be color-coded, depending on the tube additives or specific purpose.

Evacuated blood tubes are typically made of plastics such as polypropylene or PET to minimize the risk of breakage, although glass evacuated blood tubes are also available. Available as plain, empty tubes, many are pre-loaded with additives or preservatives that stabilize the blood sample or contain gel separators to facilitate the separation of blood cells from serum or plasma.

Evacuated blood tubes are widely employed in hospital blood collection (phlebotomy) departments and in other clinical, veterinary, and research settings. Once filled, evacuated blood tubes can be securely stored or transported for subsequent analysis of serum, plasma, or whole blood by clinical chemistry, blood counts, or other tests.

Types of Evacuated Blood Collection Tubes
• Red top: plain tubes without additives; for serum samples
• Purple top: contain EDTA anticoagulant; for clinical hematology procedures
• Green top: contain heparin; for plasma samples
• Gray top: with added fluoride or oxalate; for glucose determinations
• Blue top: with sodium citrate; for coagulation testing
• Other additives and colored closures