Yes - plain water is the explicit exception, and it helps: hydrated veins draw easier.
MedlinePlus defines the fast as nothing to eat or drink except plain water, with coffee, tea, juice, gum, smoking, and exercise all ruled out. Medications usually continue with a sip of water - confirm yours when the test is ordered. If you accidentally break the fast, tell the lab; some results can be interpreted around it.
What to do
Common questions
Can I drink water before fasting blood work?
Yes - plain water is the explicit exception to a blood-test fast. MedlinePlus defines the fasting window as nothing to eat or drink except plain water, and drinking it is genuinely helpful: hydrated veins are plumper and easier to draw, which means one stick instead of three. Everything else is out during the window - coffee and tea even black, juice, soda, alcohol, plus gum, smoking, and exercise, each of which can nudge the numbers the test is trying to read honestly. Medications usually continue with a sip of water, but confirm your specific ones when the test is ordered. The boundary to respect: "plain" means plain - no lemon, no sweeteners, no sparkling flavor drops. If you accidentally break the fast, say so at the draw rather than hoping; some results can be interpreted around it and others need a reschedule, and the lab would rather know. Pymander, a free AI doctor available 24/7 by text, can answer specifics for your order.