Precautions For Blood Collection Operation And Inspection

1. Blood collection equipment: disposable syringes and test tubes are often used for blood collection. Syringes and test tubes must be dry and clean. Do not use alcohol for disinfection.

2. Blood collection operation: aseptic operation must be performed. The skin at the blood collection site must be dry. The tourniquet must not be tied for too long. The speed of the blood collection must not be too fast to prevent the blood cells from rupturing. After blood collection, the needle should be removed and the blood should be slowly moved along the tube wall Pour into the test tube.

3. Prevent the escape of gas: Collect blood gas analysis samples. There should be no cavitation in the syringe when blood is drawn. Use a small rubber to seal the needle immediately after drawing out to isolate the air. Because the partial pressure of oxygen in the air is higher than that of arterial blood, and the partial pressure of carbon dioxide is lower than that of arterial blood; when measuring the carbon dioxide binding force, the blood sample container should also be sealed tightly to avoid prolonged contact between blood and air, which will affect the test results.

4. Prevent decomposition and self-change: send blood for inspection as soon as possible after blood collection. Because some chemical components in the blood are easily decomposed after in vitro, their content changes, such as blood glucose and enzyme determination, over a long period of time, due to the glycolysis of blood cells, blood glucose can be reduced and enzyme activity can be changed. Some chemical components are differently suspended inside and outside the cell. If the isolation time is too long, the concentration inside and outside the cell will change, which will affect the determination result. Such as creatine kinase, lactate dehydrogenase, electrolytes, etc.

5. Prevention of pollution: Some inspection items have strict requirements, and the blood collection equipment and specimen containers must be chemically cleaned. For items such as blood ammonia, copper, zinc, iron, etc., because their content is extremely low, slight pollution will affect the results. When measuring amylase, it is necessary to prevent saliva contamination, because saliva contains a large amount of amylase, pollution will cause pseudo-amylase to increase.

6. Prevent hemolysis: Perform various biochemical tests to prevent rupture of blood cells and hemolysis. The intracellular and extracellular concentration changes due to hemolysis can increase potassium, bilirubin, chloride, inorganic phosphorus, ALT, AST, LDH, etc., Calcium, AKP, etc. are reduced, and hemolysis interferes with the reaction process of some experiments: for example, hemoglobin can directly inhibit the activity of lipase and reduce lipase. Hemolysis can affect experiments with a red end point of the color reaction, such as the enzymatic determination of blood glucose, cholesterol, triglycerides, diazonium reaction of bilirubin, and diacetoxime method of urea.