Importance of proper order and filling of blood collection tubes

Kalstein blood sample collection tubes are normally glass, plastic, PET, PP, PS vacuum tubes with a soft plastic cap, which allows it to be pierced by a needle by gentle pressure.

There are several types of vacuum tubes that differ in the color of their cap. Each cap color indicates the additive, or absence thereof, contained in the tube. For example, the lilac or violet plug tubes contain EDTA; the light blue ones contain citrate, etc.

The advantage of these vacuum tubes is that the person taking the sample does not come into contact with the needle, thus avoiding the risk of infection.

What is the necessary order in the extraction of venous blood?

The order of use of the tubes is important to prevent contamination of the samples by unwanted anticoagulants. They must follow the following order:

• Tube for serum analysis. Without anticoagulant

• Tube for coagulation tests. With sodium citrate as anticoagulant.

• Remaining tubes with anticoagulants. EDTA, Lithium heparin, gasometry syringes or tubes for VSG.

The citrate tube, intended for coagulation tests, must always be removed before those with other anticoagulants. In this way the sample is not contaminated with EDTA or Lithium Heparin, which can interfere with the coagulation study. If it is the only tube to be extracted or has to be the first, a discard tube should be filled with about 5 ml of blood beforehand, in order to eliminate the possible contamination of the sample with tissue thromboplastin from the puncture site. Contamination with tissue thromboplastin or the aforementioned anticoagulants will alter the study of coagulation of the sample.

What are the tubes for collecting venous blood?

The most used tubes, for the collection of venous blood samples, are the following:

• Tube without anticoagulant: Used to obtain serum. They do not carry anticoagulant although they do contain activators, which facilitate clot retraction, and separator gel, which facilitates the separation of serum and clot after centrifugation.

• EDTA tube: Contains tripotassium EDTA as anticoagulant. It is the tube used for hematology, blood bank and other tests. With it you get anticoagulated whole blood.

Lithium Heparin Tube: Contains Lithium Heparin as anticoagulant. It is used to perform biochemical determinations and some special techniques. With it, anticoagulated whole blood is obtained to obtain plasma after centrifugation. Not suitable for determination of lithium in blood.

• Citrate tube (for coagulation): They contain as trisodium citrate anticoagulant. Citrate comes in a preset amount to mix with a fixed volume of blood; The exact proportion of blood and anticoagulant is crucial in the performance of coagulation tests, since if it is not adequate, the results are altered. With it the plasma is obtained, after centrifugation of the anticoagulated blood.

Citrate tube (for erythrosedimentation): It also contains as trisodium citrate anticoagulant, although the concentration is different than in coagulation citrate. It is used exclusively for the determination of the Globular Sedimentation Rate. With it you get anticoagulated whole blood.

There are more tubes with different anticoagulants, such as sodium heparin, used for immunological and biochemical determinations. Also for breathalyzer tests, where a tube with potassium oxalate and sodium fluoride is used.

In Kalstein we put an excellent range of blood collection tubes. That is why we invite you to take a look in our catalog available HERE