In general, it is not recommended to drink water when having blood drawn on an empty stomach, but a little bit of plain water will not affect it. Do not eat or drink after 10:00 p.m. on the first day of the blood draw. The purpose of fasting blood collection is to avoid the impact of eating and some daytime activities on the results of the blood draw, so it is required to fast from water for more than 8 hours to collect blood in the morning. However, this is not absolute, not all blood tests require fasting, some blood tests such as A function, blood routine, microchip cancer test, preoperative four items, coagulation routine, etc. are not required. However, biochemical indicators such as liver and kidney function, electrolytes and blood lipids are affected by eating, so fasting is required. I don’t know what kind of test is done, if it is not clear, water can be drank appropriately, but no drinks, tea, etc., and don’t eat anything.