Vacutainer Blood Collection Tubes
History: Vacutainer technology was developed in 1947 by Joseph Kleiner and is currently marketed by Becton Dickinson (B-D). The Vacutainer was preceded by other vacuum-based phlebotomy technology such as the Keidel vacuum. The plastic tube version, known as Vacutainer PLUS, was developed at B-D in the early 1990s by E. Vogler, D. Montgomery and G. Harper.
Vacutainers are widely used in phlebotomy in developed countries due to safety and ease of use. Vacutainers have the advantage of being prepared with additives, allowing easy multi-tube draws, and having a lower chance of haemolysis. In developing countries, it is still common to draw blood using a syringe or syringes.
Vacutainer tubes may contain additional substances that preserve blood for processing in a medicallaboratory.Using the wrong tube may make the blood sample unusable for the intended purpose. These additives are typically thin film coatings applied using an ultrasonicnozzle.
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 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 serum accumulating at the top. Tubes containing gel can be easily handled and transported after centrifugation without the blood cells and serum mixing.
The meanings of the various colours 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, therefore the sequence is standardized so that any cross-contamination of additives will not affect laboratory results.
The Vacutainer needle isdouble-ended.The inner end is encased in a thin rubber coating that prevents blood from leaking out if the Vacutainer tubes are changed during a multi-draw, and the outer end which is inserted into the vein. When the needle is screwed into the translucent plastic needle holder, the coated end is inside the holder.
When a tube is inserted into the holder, its rubber cap is punctured by this inner needle and the vacuum in the tube pulls blood through the needle and into the tube. The filled tube is then removed and another can be inserted and filled the same way. The amount of air evacuated from the tube predetermines how much blood will fill the tube before blood stops flowing.
Each tube is topped with a colour-coded plastic or rubber cap. Tubes often include additives that mix with the blood when collected, and the colour of each tube’s plastic cap indicates which additives it contains.
A Blood collection tube expires because over time the vacuum is lost and blood will not be drawn into the tube when the needle punctures the cap.
Blood Culture Bottle: Sodium polyanethol sulfonate (anticoagulant) and growth media for microorganisms. Usually drawn first for minimal risk of contamination. Two bottles are typically collected in one blood draw; one for aerobic organisms and one for anaerobic organisms.
Plain Red: No additive: Serum: Total complement activity.
Gold/Yellow top: Clot activator and serum separating gel.
Lavender/Purple:EDTA Complete blood count Blood grouping.
Grey Top: Sodium fluoride Blood glucose level.