Talking about the quality of vacuum blood collection tube

The collection of vacuum venous blood samples is a major improvement over traditional blood collection methods. Because the blood collection procedure is completed in a fully closed system, the possibility of blood contamination and cross-infection is fundamentally excluded; and because of its simple structure and convenient use, it is easy to popularize and popularize. However, there are many brands of vacuum blood collection tubes on the market at present, and poor product quality can directly affect the test results. Here the author talks about some factors that affect the quality of vacuum blood collection tubes. Please correct me if there is any inaccuracy.

1. Silication quality of vacuum blood collection tubes
There are many types of silicone oils used for the treatment of the inner wall of the test tube, including those soluble in water and insoluble in water, those soluble in organic solutions and those insoluble in organic solutions, and the viscosity of which is extremely fluid and semi-solid. It is not an easy task to select a silicone oil with good chemical inertness and physiological inertness that is suitable for the treatment of the inner wall of the blood collection tube. Well siliconized test tube, the inner wall should be very smooth. Through a simple water-passing experiment, the quality of the inner wall of the test tube can be identified. Put 2 ml of water into the test tube and pour it out. The inner wall of the siliconized test tube is absolutely free of scattered small water droplets remaining on it. So it is conceivable that the vacuum tube without the phenomenon of blood cells hanging on the wall has laid a good foundation for the separation of high-quality serum.

2. The effect of the uniformity of EDTA-K2 addition on blood routine results
Because glass tubes have great hidden dangers in terms of safety performance, it has become a trend to use special plastic PET test tubes instead of glass tubes. Due to the good hydrophobicity of the PET test tube, the production difficulty of the vacuum tube is greatly increased. It is well known that when a liquid EDTA-K2 solution is added to a PET test tube, due to the hydrophobicity of the PET test tube, the liquid EDTA-K2 will form a block at the bottom of the test tube, the mouth of the tube or other parts after a period of time due to the partial loss of water. crystallization, greatly reducing its solubility. Because large EDTA-K2 crystals cannot fully contact with blood and dissolve in blood samples in a short time, platelet aggregation is likely to occur, the results of white blood cell classification are not satisfactory, and even partial coagulation of blood samples occurs. We know that the optimal concentration of EDTA-K2 anticoagulant selected for whole blood cell analysis is 1.5-2.2mg/1ml whole blood. If the concentration of EDTA-K2 is too low and the anticoagulation strength is not enough, platelet aggregation will occur; if the concentration of EDTA-K2 is too high, especially when there are large EDTA-K2 crystals, the local blood cells will be in a hyperosmotic state. The cells will shrink temporarily, which can lead to poor white blood cell classification results, etc. In order to avoid crystallization caused by water loss, in an ideal blood routine vacuum blood collection tube, EDTA-K2 crystals should be very fine and evenly distributed on the inner wall of the test tube. In this way, once the blood enters the test tube, the evenly distributed EDTA-K2 can be quickly and fully mixed with the blood, thus preventing the abnormal phenomenon of blood routine results due to the vacuum blood collection tube.

3. Application evaluation of separating gel and coagulant
Separation gel accelerator tube is the most common type of tube used in hospital vacuum tubes, but it is not easy to make such a tube well. The key to evaluating the quality of the separating gel accelerator tube is in the following aspects:
①Use the same blood sample and compare it with the blank tube to see if there will be deviations in the content of some ions.
②Put the collected blood sample tube containing separation gel in a water temperature box, and adjust the temperature to 38-39 ℃. After the blood sample is fully coagulated, centrifuge, and then check whether there are oil droplets in the serum. Since oil droplets can cause fatal clogging of biochemical probes, there have been many reports on the existence of this phenomenon.
③ Exclude the hemolytic factor caused by the incorrect blood collection method. Due to the inferior production process, the organic solvent remaining in the separating gel or coagulant is the culprit in destroying the blood sample. This damage is often manifested in the presence of more hemolysis in the specimen, with separating gel particles floating in the middle of the serum. It is also worth mentioning that the well-known foreign vacuum tube companies have stated that the blood coagulation tube or the coagulant separation gel should be centrifuged after collecting blood samples for half an hour, which can largely ensure the accuracy of the results.

4. Prevent liquid mildew in vacuum blood collection tube
The sodium citrate anticoagulant test tube used for blood coagulation and erythrocyte sedimentation rate has high requirements on the environment and the water used for dissolution during production. If the process and production environment are improper, or the purity of the dissolved water used does not meet the requirements, etc., the sodium citrate solution in the test tube of the produced product will produce floccules (mold growth) after a period of time, which will cause inspection. The result is distorted. Due to the good hydrophobicity of PET tubes, these tubes are not specially packaged and are recommended to be used up within three months.

In addition to the above, the heparin tube and potassium oxalate/sodium fluoride tube are not technically special due to their relatively small dosage, so they will not be described here. It is also worth mentioning that the vacuum tube is affected by the altitude, so the high-altitude area should choose the high-altitude vacuum blood collection tube.