Drinking a sip of water can test the blood, requiring the blood test to be fasting, so that for many of the indicators more accurate. But a sip of water will not have much effect on the testing of indicators, basically. Blood tests include routine blood tests, liver and kidney functions, electrolytes, blood glucose, blood lipids, and even thyroid function, glycosylated hemoglobin or tumor indicators. If the patient eats after eating, that is, after eating a liquid or semi-liquid food, or even rice or bread, it may have an effect on liver function, blood lipids, blood glucose and other tests. However, it will not have any effect on the blood routine, tumor index and hepatitis B five tests.