Does eating breakfast affect blood drawing?

When it comes to blood drawing, everyone is very familiar with it. Whether it is a physical examination or a disease examination, blood drawing is required. Through blood tests, we can clearly see the gap between various indicators in the human body and normal values, thereby determining the source of the disease in the human body. Moreover, you are generally not allowed to eat breakfast on the morning of the blood draw. So, does eating breakfast have any effect on blood drawing?

Usually, the examination of many diseases requires blood drawing. For most blood tests, you should keep fasting before the test to avoid some influence on the test results due to food, which further affects the judgment of the disease. Therefore, you should not eat breakfast before the blood test. Here are some precautions for blood tests.

You need to pay attention to the precautions before having a blood test.

1. When seeing a doctor, be sure to cooperate with the doctor to write your name correctly and neatly. Avoid confusion with the same or similar names and avoid inconvenience caused to you.

2. Fasting blood must be collected for biochemical tests. Generally speaking, most of the tests that require fasting blood draw are biochemical tests. For example, liver function, sugar, protein, lipids, and various inorganic ions (potassium, sodium, calcium, phosphorus, etc.). In special cases, blood can be drawn six hours after a light meal as directed by a doctor; however, blood must be drawn 12 hours after a meal for a blood lipid test.

3. Fasting blood refers to venous blood drawn in the early morning before meals, about 12 to 14 hours after the previous meal. Since the gastrointestinal digestion and absorption activities are basically completed 12 to 14 hours after a meal, the various biochemical components in the blood are relatively constant. The various values ​​measured at this time can more truly reflect the biochemical changes of the body, and thus help in the diagnosis of the disease.

4. On the day of blood collection, do not wear clothes with cuffs that are too small or too tight to avoid having your sleeves unable to be rolled up during blood collection or having your sleeves too tight after blood collection, which may cause hematoma in the blood vessels in your arm.

5. Ask your doctor clearly about different test items and get different treatments. For example, for blood sugar test, postprandial blood sugar must be tested after eating; pre-meal blood sugar must not be tested in the morning; before blood lipid test, it is best not to eat foods with too much fat, such as pork rib soup, steamed pork with rice flour, etc.

Therefore, before having a blood test, especially when checking liver function, you should start fasting the night before. In particular, do not drink alcohol or some alcoholic beverages, and it is best not to do strenuous exercise before the examination. You can have your blood drawn after you have rested properly at the hospital.