Vacutainer

A blood collection tube is used in medicine as a sample container for collection and processing of blood samples. Similarly constructed are systems for urine samples. Furthermore, it makes it simple to transport and short-term storage of the samples.

Blood collection tubes are made of transparent plastic and are fitted at the top with a special connection. Among others, there are adapters for the luer lock system.

Design and operation

There are two fundamentally different systems that record by aspiration or vacuum the samples. For both systems are tubes with various additives, which are standardized and are color-coded.

Aspiration

A blood collecting tube according to this system (eg Kabevette ®, Monovette ® ) is the design of a syringe. By pulling out the piston creates a vacuum, which accelerates the blood. The stamp may be bent after full pull-out, sending and storing the Monovette simplified by shortening its length. Since the piston engages at full retraction, can with a Monovette even before the puncture already a negative pressure is generated, so you can lose weight even after the vacuum principle blood with a Monovette, but the needle should be inserted into the blood vessel first and then the Monovette must be connected, otherwise prevails over pressure equalization via the cannula is no vacuum in the Monovette more.

A Monovette can therefore be used both by the Aspirationsprinzip and the vacuum principle.

Vacuum system

Within the sample container of this type (eg Vacuette ®, Vacutainer ®), there is a negative pressure from the outset. It is inserted to the connected to the puncture needle adapter, the blood is sucked in by this negative pressure. An advantage of this system is that the sucked-in amount of blood is more constant than in the Monovette. Disadvantage compared to the aspiration is that the built-up vacuum for blood sampling does not vary and the vein conditions can be adjusted.

Color coding

Depending on the used additive to inhibit blood clotting ( depending on the desired form of analysis ) distinguishes different types of sampling tubes:

• Citrate ( green ( Monovette ) or light blue (negative pressure ), eg for INR / Quick, PTT, D-dimer determination)
• EDTA ( red ( Monovette ) or purple (negative pressure ), eg for the blood picture or HbA1c)
• Lithium heparin (yellow- orange ( Monovette ) or green ( negative pressure), clinical chemistry )
• Serum ( white ( Monovette ) or red ( negative pressure), clinical chemistry, serology )
• Sodium citrate ( purple ( Monovette ) or black (negative pressure), specially shaped tubes for the determination of the erythrocyte sedimentation rate )
• Sodium fluoride ( light yellow ( Monovette ) or gray (negative pressure ), eg for lactate or glucose)

• Blood
• Laboratory Medicine