Can you drink water before a blood test?

When required to fast before a blood test, patients may take this to mean they can’t drink anything at all – including water.

But keeping hydrated actually means a smoother blood draw. “Hydrated veins are easier to find, and that means easier to draw from,” said Michael Hawks, Administrative Director of Laboratory, Aspirus Riverview Hospital and Clinics. “Drink plenty of water before having any blood test.”

For those participating in National Blood Donor Month this January, the same philosophy applies.

“Consume a reasonable amount to keep hydrated,” said Hawks. “The object of drinking water is to stay hydrated as one person normally consumes water during the day.”

Black coffee might also be allowed, depending on the hospital and its requirements.

“Fasting means to keep your body at a steady state with nothing altering its functions. Coffee would alter its function, so drinking coffee would not be truly fasting,” said Hawks. “But, again, it is dependent on the hospital. I have heard it both ways, and we would not turn away someone who was fasting with the exception of drinking black coffee – we would just put a comment into the record to reflect it.”

To find a blood drive, visit

News Desk
Author: News Desk