Recommendations for collection and processing of blood samples

The measurement of hemorheological index is more complicated, it is a comprehensive expression of blood composition and its properties. The detection of blood rheology is different from other test items, and the accuracy of the test results is affected by many factors. In order to provide a reliable scientific basis for clinical medicine and scientific research, the following suggestions for specimen collection and processing are put forward.
1. Preparation before blood collection
The night before blood collection, fasting of fatty foods of livestock and poultry, and discontinuation of various drugs, for patients with diarrhea and application of weight-loss drugs, the weight-loss drugs should be stopped for 3 days after the diarrhea is cured. Rest quietly at night to avoid tension, and usually collect fasting blood in the morning.
2. Configuration of anticoagulant
The use of anticoagulants has a significant impact on the detection of blood rheological indicators. We use commercially available heparin vacuum blood collection tubes or 2 ml of heparin containing 12,500 units and 8 ml of distilled water to mix well, divide into 100 test tubes, and place them in an oven to dry. , put 4 ml of whole blood in each test tube and mix thoroughly to avoid the destruction of blood cells caused by violent shaking and no small clots.
3. Requirements for blood collection
3.1 Vascular selection
In general, the venous blood of the elbow should be selected, and the blood vessels are required to be obviously free of skin diseases, and blood collection from small veins should be avoided as much as possible.
3.2 Technical requirements for blood collection
We choose a disposable vacuum blood collection tube or a 10 ml disposable syringe. The needle is No. 8. The equipment used must be dry and clean. When collecting blood, we strive to hit the spot and avoid air bubbles. The blood collection process should be smooth. , so that the blood is slowly injected into the test tube along the blood vessel wall, and the blood sample must not be mixed with air bubbles and small clots, otherwise the sample must be re-collected.
3.3 Application of cuffs
The purpose of selecting the cuff is to fix the vein, and it is easy to see the position of the vein for puncture. However, the size of the cuff pressure, the length of time, and the interval between relaxation and actual blood collection have an impact on the blood flow detection results. It is generally believed that empty puncture After the success, the blood pressure should be relaxed for more than 5 seconds before starting blood collection, otherwise it will cause the blood viscosity to increase and errors will occur.
4. Processing of blood samples
The temperature of the laboratory should be controlled at about 25°C, and the blood should be tested within 20 minutes to 4 hours after the blood is separated from the body. If the storage time is too long, the carbonic acid in the whole blood will be decomposed, the partial pressure of carbon dioxide will drop, and the pH value will change, which will make the blood viscosity measurement result. It is too high. After the blood is left to stand, because the blood is formed to settle in the lower part of the test tube, and the upper part is the plasma component, so each time a blood sample is tested after standing, it must be thoroughly mixed. Tilt the test tube and rotate it a few times. , and then shake gently, use a pipette to draw 1/2 of the blood sample from the bottom and then slowly inject it back along the test tube wall. Before the test, check whether the blood samples meet the test requirements one by one, whether there is hemolysis and blood clots, and make sure that there are no air bubbles, small blood clots, water droplets, dust, etc. in the blood samples, otherwise the results will be significantly different.