Whether you can drink water before the blood test, and the amount of water you drink, depending on the test items, different items require different, common situations are as follows: 1, the test does not recommend drinking water: pregnant women perform liver and kidney function tests, glucose tolerance tests, lipid tests, thyroid function tests, myocardial enzyme spectrum tests and other items, it is not recommended to drink water and it is best to do so on an empty stomach. However, if a pregnant woman is really thirsty and cannot tolerate it, she can drink a small amount, but not too much to avoid blood dilution, which will affect the accuracy of the test results and delay the diagnosis of her condition. Especially in early pregnancy tests, attention should be paid to fasting and water fasting to ensure that the examination goes smoothly; 2. Tests that are not affected by drinking water: such as routine blood tests, coagulation function, blood group determination, hepatitis B surface antigen determination, HIV, syphilis serology tests and Down syndrome screening, etc., do not require fasting and can eat and drink water, which does not affect the test results. It is advisable to consult your doctor before the test, as different hospitals may have different requirements. For example, it is usually not necessary to fast during early pregnancy for HCG and progesterone blood tests, but some doctors may require fasting in order to avoid minor effects of food and water on the test.