Drinking two sips of water during a fasting blood test will not affect the results much, but it is recommended to avoid drinking water as much as possible.
Tests that require fasting blood draws are usually for checking liver and kidney functions, etc. If you drink a small amount of plain water or purified water before the blood draw, it will not have a great impact, but if you drink a large amount of water, it may lead to dilution of the blood, thus affecting the accuracy of the test results.
If you drink beverages, tea or coffee before the fasting blood draw, it may affect the body and make the test results inaccurate. For example, sugary drinks will affect the accuracy of fasting blood glucose; drinking coffee will stimulate the secretion of catecholamines, leading to an increase in blood glucose.
If there is any abnormality in the fasting blood test result after drinking a small amount of water, it should be explained to the doctor in time, and if the doctor thinks it is necessary, the fasting blood can be taken again for examination.