(1) Patients who need blood test are generally required to fast 12 hours before blood collection (but not too fast, resulting in low blood sugar results and high serum bilirubin). Avoid eating high-fat and high-protein food, drinking and smoking for three days before blood collection. Otherwise, the results of blood lipids (such as triglycerides) and some serum enzymes (such as alanine aminotransferase, lactate dehydrogenase, uric acid, r- glutamine transaminase, etc.). ) will increase, and even the serum will be turbid, which will affect the whole test result. Patients undergoing glucose tolerance test should be given proper amount of carbon and water chemicals three days before the test according to the doctor's advice, which is conducive to obtaining correct results.

(2) Matters needing attention in urine sample collection. The quantitative determination of urine sugar, urine amylase and urine protein is suitable for morning fasting urine, and morning urine is recommended for urine pregnancy test (to avoid dilution of urine with a large amount of drinking water, the result will be false negative).

(3) Before fecal occult blood examination, patients should be vegetarian for 3 days before sampling, otherwise the result is false positive.

2. Specimen collection time

Blood biochemical examination generally needs to collect blood in the morning when it is quiet on an empty stomach. Because various chemical components in the body are regulated by many factors: for example, a large amount of glucose and lipid substances are absorbed into the blood after eating, which increases blood sugar and blood lipid, and reduces free fatty acids and inorganic phosphorus; After strenuous exercise, lactic acid, pyruvate, lactate dehydrogenase, transaminase and creatine kinase increased and blood sugar decreased; Drinking more water can dilute blood and urine. Therefore, when doing blood tests and urine tests, we must grasp the collection time. When taking blood during infusion, it is necessary to avoid the influence of infusion components and the dilution of blood and urine, such as supplementing potassium, sugar and alkali during infusion, which will affect the binding force of blood potassium, blood sugar and carbon dioxide.

3. Blood collection point

Adults generally take the elbow vein; Babies often use jugular vein; Newborn babies can collect umbilical cord blood; Patients in urgent need of blood transfusion should take blood from the upper limb or lower limb on the same side of transfusion, and burn patients should avoid puncturing inflammation or edema to avoid affecting the results.