Can I drink water while having a blood test? What should I pay attention to before the blood test?

Blood test is a very familiar medical examination item for modern people. Many diseases require blood sampling to test whether there are problems with relevant indicators. People are already quite familiar with the blood test process, but there are still quite a number of people who are confused about whether they can drink water before the blood test. Many people think that drinking water before a blood test will dilute the blood and affect the test results.

Drink a small amount of water before the blood test

Most people know that they need to fast and not drink water after 12 o'clock the night before a physical examination. The purpose is to ensure the accuracy of the venous blood laboratory test results during the physical examination the next day. Drinking a lot of water before a physical examination will dilute the blood and cause errors in many test values, but this does not mean that you cannot drink any water at all.

Before the physical examination, we can drink a small amount of water, but we cannot drink milk, soy milk, beverages, etc., otherwise it will affect the accuracy of the test data. Generally speaking, you only need to fast at 12 o'clock the night before the physical examination. If you have dry mouth or take special medications on the morning of blood draw, it is okay to drink 50 to 100 ml of water. As long as you don't drink several hundred ml at one time, it will not affect the results of the physical examination.

Four major precautions for blood test

1. Fasting blood collection time. Fasting blood usually refers to blood drawn in the early morning before eating, about 8-12 hours after the previous meal. After eating, many substances in the blood will show temporary changes, which cannot reflect the true condition of the body. Fasting blood is usually collected in the morning, but if necessary, it can also be collected 6 hours after a light meal. You should maintain your normal eating habits 2 weeks before the blood lipid test, and blood should be drawn 12 hours after a meal.

2. Do not exercise too much before blood collection. One type of exercise is static, meaning it does not last long but is of high intensity, such as weightlifting, throwing a ball, etc. It utilizes the energy stored in the muscles and has little effect on the test. Another type of exercise is dynamic, that is, it lasts for a long time and has low intensity, such as long-distance running, swimming, cycling competitions, etc. It requires a lot of calories to maintain and has a greater impact on the test results. It should be avoided as much as possible within 2 days before the test.

3. Don’t take large amounts of vitamins before blood collection. Don't take large amounts of vitamins before blood collection, otherwise it may cause some test results to be distorted. For example, taking large doses of vitamin C can affect the results of urine sugar.

4. Please extend your ring finger for peripheral blood sampling test. Peripheral blood sampling is suitable for testing items with blood volume less than 0.1 ml, such as peripheral blood glucose. The side of the left ring finger tip is usually chosen. First, there are more blood vessels in this area, and second, the cut will not affect the finger's continued contact with objects.