Laboratory medicine is through modern scientific instruments or reagents to make certainty or auxiliary diagnosis of human diseases, to provide doctors with an important reference basis for diagnosis and treatment of diseases. However, the test results are also affected by physiological factors, disease factors or drug factors, etc. It has been reported that the error before analysis reaches 40% of the total error of the test. The factors affecting the test results are manifold, including the patient’s living habits and conditions, such as diet, alcohol, beverages, medication, labor and exercise, working conditions, mental emotions, blood sampling time, physiological and pathological conditions. Therefore, before drawing blood should take the initiative to understand the matters that should be noted before the test, will affect the test results of the various factors to a minimum, we suggest that before the test should pay attention to the following matters: 1, a variety of venous blood test, it is best to draw blood on an empty stomach in the morning from 7:00 to 10:00 a.m., because the organism by the night’s rest, the body’s content of the various components of the material at a relatively constant level. Before the blood is drawn, fasting and drinking milk are prohibited to prevent the absorption of certain ingredients in food into the blood to affect the test results. In general, you can drink normal water, and it is a wrong concept not to drink water before blood sampling, because not drinking water can cause blood concentration and make various test results falsely higher. 2, check blood lipids, blood rheology [blood viscosity] should be fasted the day before animal fats, meat, and must be fasted for 12 hours before blood sampling. 3, check liver function, kidney function, cardiac enzymes, etc. the day before do not do strenuous exercise, do not drink alcohol, do not drink coffee, do not take drugs that have an impact on the liver and kidney. 4.Blood glucose test should be fasted 12 hours before blood sampling, postprandial blood glucose refers to normal diet two hours after blood sampling to check blood glucose. 5, urine test to the first urine in the early morning is good, because urine in the body after a night of concentration, the concentration of pathological substances is relatively high, easy to be detected. You can bring your own clean container with a lid, keep 10-20 ml of mid-range urine to send for testing, and you should avoid mixing menstrual blood, leukorrhea, and feces. Do not use a large dose of vitamin C the day before. 6, urine early pregnancy test do not drink a lot of water before the urine collection, in order to prevent the dilution of urine, it is best to use the first concentrated urine in the morning to send the test. 7, urine culture three days before the best stop using antibiotics, should receive a special sterile cup, the morning after cleaning the urethra mouth to stay in the first mid-range urine for testing. 8, fecal specimens should be taken with pus and blood part of a soybean-sized, covered and sent for testing, should avoid urine, water and other components mixed. 9, fecal occult blood test three days before fasting animal food, select the inner and outer layer of feces as soon as possible to send for testing. 10.The result of the test will be collected at the report issuing office with the fee receipt slip within the same day. Quantitative tests may have 10% physiological fluctuations when blood is drawn at different times of the day, and qualitative tests such as two halves may have a false error of less than 5%, and different hospitals using different methods and reagents may also have certain differences. If you have any doubts about the test results, you should apply for a free review within the same day.