When people go to the hospital for medical treatment or physical examination, drawing blood on an empty stomach is one of the common and important examinations, but many people have wrong ideas and blind spots about drawing blood on an empty stomach. According to statistics, about 60~80% of the test errors occur before blood drawing, which is a waste of time, and the most serious will cause the doctor's misjudgment, so we must not be careless!

Effect of fasting on blood drawing items

Blood test of liver function: After eating, serum components may change. After adding chemical reagents, normal people's serum will produce different degrees of precipitation, especially those who eat high-protein or high-fat foods, which will produce obvious precipitation. The reported results will make doctors misdiagnose hepatitis. In order to make the results more accurate, blood test should be done on an empty stomach when testing liver function.

Blood tests of renal function: Some tests will be affected by diet, digestion and metabolism, especially biochemical tests. If false laboratory tests are caused or doctors misdiagnose them, the consequences will be very serious.

Renal function examination requires fasting for 8~ 12 hours, because blood changes with food. For example, blood urea will be affected by high-protein food, trauma, infection and so on. , which will lead to inaccurate test results. Therefore, before renal function examination, we must remember to keep an empty stomach.

Effect of fasting on blood content

Blood sugar: Blood sugar and some biochemical and metabolic indexes are greatly influenced by diet. After eating, food quickly breaks down into small molecules and enters the blood, affecting various indicators. Fasting blood test is actually to compare under a unified "standard" and has clinical significance.

The definition of "fasting" is that you haven't eaten for at least 8 hours. You can't eat any food the night before, but you can drink a little boiled water. As for whether to take other drugs, be sure to follow the doctor's advice. Excessive fasting means that the fasting time is more than 8~ 10 hour, and triglycerides, glycerol and free fatty acids increase instead of decreasing, so the longer the fasting time, the better.

Blood viscosity: Blood viscosity requires fasting blood collection. Diet has a great influence on blood lipids. Within 6 hours after eating fatty food, the blood triglyceride concentration will continue to rise, and then gradually fall back to a stable state after 6-8 hours.

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