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Performance index of vacuum blood collection tube material

The vacuum blood collection tube series has become the mainstream for the collection of blood samples. Due to the natural coagulation of blood after blood collection in the past, the time from centrifugation to measurement of blood is long, which affects the analysis results and speed. In order to rapidly advance the detection technology, separating gel was added to the blood collection tube, and the coagulant shortened the blood coagulation time. Test specimens and report results in the shortest time possible. At the same time, it reduces the potential risks of biological safety such as cross-infection, standardizes the blood collection technology of the laboratory department, improves the quality of the test specimens, and facilitates the treatment of patients. However, with the increasing application of separation gel-promoted blood collection tubes in clinical practice, there are many misunderstandings and related problems that are worth noting in their use. It is necessary to introduce these problems.
The extensive use of automated instruments and the preservation of blood have put forward higher requirements for the stability of the original characteristics of blood samples, which makes the vacuum blood collection technology break through the requirements for safety only, and the accuracy, the original characteristics of the specimen, the maintenance time and the coordination of the tube machine. , test tube strength and other performance indicators can not be ignored, the factors that affect the original characteristics of the specimen and the detection accuracy are as follows.

1. Material of vacuum blood collection tubes: In the past, blood collection tubes were mostly made of glass materials. The pH of ordinary glass was far different, and the possibility of hemolysis was greatly increased. However, the glass test tubes made by the tube drawing process were densely distributed with linear grooves, and the depth and thickness were irregular, which led to the hanging of cells. The main component of the glass test tube is hydrophilic silicate. After blood collection, the inner wall of the glass test tube can form a water-absorbing layer that absorbs water molecules. Therefore, the separation gel cannot directly adhere to the inner wall of the glass test tube. With the extension of storage time, substances such as potassium or enzymes in red blood cells can diffuse into the serum through the water-absorbing layer of water molecules. Therefore, the period of preservation of serum in the original state of glass blood collection tubes should be 2-3 days. Plastic blood collection tubes are commonly made of polyethylene terephthalate (PET) material, which is hydrophobic and does not produce a water molecule layer on the tube wall. Separating glue can firmly adhere to the inner wall. It could not diffuse into the serum, so the serum potassium content remained unchanged for 8 days after refrigerated storage. PET plastic vacuum blood collection tubes can store specimens at -20℃, which is difficult to achieve with ordinary plastic test tubes and glass test tubes. Therefore, it is better to use PET plastic blood collection tubes as much as possible when choosing vacuum blood collection tubes.

2. Sealant plug: The quality of the sealant plug directly affects the vacuum performance of the test tube and the original state of the blood sample. It is recommended to use butyl rubber instead of natural rubber. The natural rubber packing is seriously extravasated and is a material that can cause hemolysis. , Many organic fillers and additives (including paraffin oil, silicone oil, softeners, colorants, etc.) will climb down the glass tube wall in a vacuum state, these substances especially affect the water solubility of vacuum-dried heparin substances and cause blood clotting. In addition, its air permeability and water permeability do not meet the technical requirements of the vacuum tube, the vacuum loss is serious, and the junction of the tube plug can be seen that the plug is seriously sticking to the wall. But butyl rubber has good sealing performance, and the dissolved substances are greatly reduced, so that the blood collection tube can keep the vacuum constant for 24 months even under the negative pressure of 101.3kPa. The constant vacuum enables the blood collection object to maintain a relatively accurate blood collection volume even if there are differences in blood pressure and blood viscosity, as well as changes in the temperature of the blood collection environment, and the actual blood collection volume error can be controlled within ±5%.