How long before a blood test should you stop drinking water and eating?

Blood tests require fasting for 6 to 8 hours beforehand, during which you should not drink water or eat food.

Routine blood tests include complete blood count, liver function, kidney function, blood glucose, blood lipids, and electrolytes. It is generally recommended that you avoid drinking and eating for 6 to 8 hours prior to the blood test. This is because consuming food or liquids may affect the accuracy of test results and prevent an accurate assessment of your health status. Typically, blood tests are conducted in the morning; therefore, it's advised to stop eating and drinking after midnight the previous night.

In addition to fasting before blood tests, you should also maintain a light diet the night before and avoid greasy or spicy foods, as these may interfere with blood glucose and lipid measurements. You should also refrain from drinking alcohol and staying up late the night before the test, as both can affect the accuracy of liver function tests. During the blood draw, try to stay relaxed and avoid excessive tension or anxiety.