Precautions for blood collection operation and inspection

Precautions for blood collection operation and inspection

1. Blood collection equipment: blood collection multi-purpose disposable syringe and test tube. Syringes and test tubes must be dry and clean. Alcohol should not be used for disinfection.

2. Blood collection operation: it must be aseptic. The skin of the blood collection site must be dry. The tourniquet should not be tied too long. The speed of blood drawing should not be too fast to avoid blood cell rupture. After blood collection, the needle should be removed and the blood should be slowly injected into the test tube along the tube wall.

3. Prevent the gas from escaping: collect the blood gas analysis sample, there should be no vacuole in the syringe when drawing blood, and seal the needle with a small rubber 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 binding force of carbon dioxide, the container containing blood sample should also be plugged tightly to prevent the blood from contacting with air for a long time, which may affect the test results.

4. Prevent decomposition and self change: blood should be sent for examination as soon as possible after blood collection. Because some chemical components in blood are easy to decompose after in vitro, the content changes, such as the determination of blood glucose and enzymes. If the time is too long, the blood glucose will decrease and the enzyme activity will change. The concentration of some chemical components inside and outside the cell will change if the time in vitro is too long. Such as creatine kinase, lactate dehydrogenase, electrolyte and so on.

5. Prevention of pollution: some inspection items are very strict, and their blood collection instruments and specimen containers must be chemically cleaned. Such as blood ammonia, copper, zinc, iron and other items, because of their very low content, a little pollution will affect the results. When determining amylase, it is necessary to prevent saliva contamination, because saliva contains a large amount of amylase, which will cause the increase of false amylase.

6. Prevention of hemolysis: for all kinds of biochemical tests, it is necessary to prevent the rupture and hemolysis of blood cells. The concentration changes inside and outside the cells caused by hemolysis can increase potassium, bilirubin, chloride, inorganic phosphorus, alt, AST, LDH, etc., and reduce sodium, calcium and AKP. Hemolysis interferes with the reaction process of some experiments: for example, hemoglobin can directly inhibit the activity of lipase and reduce the lipase. Hemolysis can affect the experiment that the end point of color reaction is red, such as diazotization reaction of enzymatic determination of blood glucose, cholesterol, triglyceride and bilirubin, diacetyl oxime method of urea, etc.