Vacutainer

A Vacutainer blood collection tube is a sterile glass tube with a colored rubber stopper creating a vacuum seal inside of the tube facilitating the drawing of a predetermined volume of liquid. Vacutainer tubes may contain additives designed to stabilize and preserve the specimen prior to analytical testing. Tubes are available with a safety-engineered closure (rubber stopper), with a variety of labeling options and stopper colors as well as a range of draw volumes.

Vacutainer tubes were invented by Joseph Kleiner and Becton Dickinson in 1949.Vacutainer is a registered trademark of Becton Dickinson, which manufactures and sells the tubes today.

Types of tubes

A tiger top tube after centrifugation to separate blood cells from serum

Vacutainer tubes may contain additional substances that preserve blood for processing in a medical laboratory. Using the wrong tube may make the blood sample unusable for the intended purpose. These additives are typically thin film coatings applied using an ultrasonic nozzle.

The additives may include anticoagulants (EDTA, sodium citrate, heparin) or a gel with density between those of blood cells and blood plasma. Additionally, some tubes contain additives that preserve certain components of or substances within the blood, such as glucose. When a tube is centrifuged, the materials within are separated by density, with the blood cells sinking to the bottom and the plasma or serumaccumulating at the top. Tubes containing gel can be easily handled and transported after centrifugation without the blood cells and serum mixing.

Vacutainer blood tubes

The meanings of the various colors are standardized across manufacturers.

The term order of draw refers to the sequence in which tubes should be filled. The needle which pierces the tubes can carry additives from one tube into the next, so the sequence is standardized so that any cross-contamination of additives will not affect laboratory results.

Containers containing coagulants

• Gold or "tiger" red/black top: clot activator and gel for serum separation
• Red top (plastic, not glass): clot activator but no serum separation gel
• Orange or grey/yellow "tiger" Top: thrombin, a rapid clot activator, for stat serum testing

Containers containing anticoagulant

• Green: sodium heparin or lithium heparin used for plasma determinations in clinical chemistry (e.g. urea and electrolyte determination). Sodium heparin collection tubes are the classically preferred tube for peripheral blood or bone marrow for cytogenetic studies. Lithium heparin is considered suboptimal for cytogenetics.^{[citation needed]}
• Light green or green/gray "tiger": For plasma determinations.
• Purple or lavender: K₂ EDTA. This is a strong anticoagulant and these tubes are usually used for complete blood counts(CBC). Lavender top tubes are generally used when whole blood is needed for analysis. Can also be used for some blood bank procedures such as blood type and screen. EDTA tubes are preferred by most molecular genetics laboratories for molecular genetic studies (DNA or RNA).^{[citation needed]}
• Grey: sodium fluoride and oxalate. Fluoride prevents enzymes in the blood from working, by preventing glycolysis so a substrate such as glucose will not be gradually used up during storage. Oxalate is an anticoagulant.
• Light blue: sodium citrate. Citrate is a reversible anticoagulant, and these tubes are used for coagulation assays.
• Dark Blue: EDTA.These tubes are used for trace metal analysis.
• Black - Used for Erythrocyte Sedimentation Rate (ESR).

Other

• Red (glass): Contains no additives.
• Light yellow: Contains sodium polyanethol sulfonate (SPS). Used for blood culture specimens or acid-citrate-dextrose(ACD), used for blood bank studies, HLA phenotyping, and paternity testing.
• Tan (glass or plastic): Contains either sodium heparin (glass) or K₂EDTA (plastic). Used for lead determinations. These tubes are certified to contain no lead.