Doctor Khanath Affirms Drinking Water Before Blood Tests is Okay, Helps Veins Hydrate for Easier Needle Insertion
A cardiologist clarifies that drinking plain water before blood tests is beneficial and helps hydrate veins for easier needle insertion, despite common misconceptions about fasting requirements. Patients should avoid food, caffeine, and sug
Doctor Khanath Kraithakul, a cardiologist and internal medicine specialist, has clarified misconceptions about fasting before blood tests. Many patients mistakenly believe they must avoid all liquids, including plain water, before blood draws, which can lead to dehydration, dry mouth, and dizziness—making the procedure more difficult and potentially affecting test results.
While some blood tests do require fasting from food to ensure accurate results, plain water is not food or a caloric beverage and should actually be consumed. Patients are encouraged to drink plain water because it keeps veins properly hydrated, makes blood draws easier, reduces the risk of fainting, and prevents dehydration that could thicken blood and skew results. The water must be pure and unmodified, consumed gradually in small sips throughout the fasting period without overdoing it.
However, patients should avoid tea, coffee, sugary drinks, soft drinks, fruit juice, candy, chewing gum, cigarettes, and alcohol before blood tests, particularly before lipid screening.
When asked why medical professionals traditionally recommend 8 hours of fasting, Doctor Khanath explained this is an outdated approach. Modern medicine allows patients to drink water as described. For certain tests like lipid panels, doctors may still require food fasting because eating affects lipid measurements, but patients can still drink water during food fasting periods.
