Blood Collection Tubes

Blood Collection Tubes
Each blood collection tube has a manufacturer's label that lists the lot number, tube volume, expiration date, and additive (if present). The lot number is useful as a reference if a manufacturing quality issue for blood tubes should occur.
Tube volume
The vacuum in a blood collection tube is controlled by the manufacturing process so that a specified volume of blood is allowed to enter the tube during a blood collection. The volume of blood that is collected will result in the correct blood-to-additive ratio. Each tube must be filled to this volume in order to ensure an optimal specimen that will not cause erroneous test results.
Expiration Date
The expiration date must be closely monitored and tube stock should be rotated to ensure that older tubes are used before they expire. A tube that is past its expiration date may lose some of its vacuum, resulting in a short-draw and an incorrect ratio of blood to additive. Some anticoagulants can also become less effective past the expiration date of the tube, and the gel in a serum- or plasma-separator tube may not perform properly.
The color of the cap indicates the additive that is inside the tube. The characteristics of several tubes that are routinely used for blood collection are summarized in the table below.
When drawing blood, the phlebotomist must draw the tubes in a specific order to avoid specimen contamination from tube additives. This order of draw is an accepted laboratory standard. Tubes or bottles for blood cultures must be drawn first. The order of draw for other tubes should follow the order listed in the table.