Does drinking water before checking blood sugar cause higher readings?

Drinking water before a blood glucose test generally does not directly affect blood sugar levels. Blood glucose tests primarily measure the concentration of glucose in the blood, and since water does not contain sugar, simply drinking water will not cause a rise in blood glucose. However, different situations may have varying effects:

1. Small amounts of water: If only a small amount of water is consumed before testing, it typically will not directly affect the blood glucose reading. This is because minimal water intake does not alter the concentration of glucose in the blood.

2. Large amounts of water: However, consuming a large volume of water shortly before the test, exceeding 100 ml, may cause fluctuations in blood volume and potentially dilute the glucose in the bloodstream, leading to a slightly lower blood glucose reading. Therefore, it is recommended to avoid drinking large amounts of water shortly before measuring blood glucose.

Note: Patients should avoid drinking sugary beverages or drinks with high sugar content before testing, as this may affect the accuracy of the blood glucose reading.