Does drinking water on the day of the physical exam have any effect?
Nov 20, 2022
Source: Cainiu Health
Dr. Yang Shuwen
Introduction
If a physical examination requires tests for blood glucose, blood lipids, liver function, and kidney function, it is generally required to fast and avoid drinking water after 8 PM the previous night to prevent affecting the examination results. However, for other examination items such as head CT scans, MRI scans, abdominal ultrasounds, and electrocardiogram (ECG) tests, drinking water normally is generally allowed and will not affect the examination results.
Whether drinking water on the day of a physical examination has an impact depends on the specific examination items. It may affect certain blood tests, but generally does not affect most imaging examinations.
Physical examinations include various tests. If the examination involves blood glucose, lipid profile, or liver and kidney function tests, fasting and abstaining from water are usually required. Typically, you should avoid eating and drinking after 8 p.m. the previous night to prevent interference with test results. For example, in blood glucose testing, drinking water can dilute blood sugar levels and affect plasma glucose concentration. In lipid testing, water intake may dilute certain substances in the blood, affecting the accuracy of lipid measurements. Liver and kidney function tests are biochemical blood tests, and drinking water can directly influence their results.
However, for other examination items such as head CT scans, MRI scans, abdominal ultrasounds, and electrocardiograms (ECG), drinking water is generally permitted and does not affect the results. For certain specific exams—such as pelvic ultrasound for women or bladder examinations—drinking plenty of water is necessary to ensure accurate results.
