FORT LEAVENWORTH, Kansas -- Getting ready for a blood test often means fasting, but that doesn’t mean you should stop drinking water. In fact, staying hydrated is one of the best ways to prepare.
“Many patients think fasting means no food or drink at all, but in most cases, you can and should still drink water,” said Capt. Teteama Bennett, laboratory manager at Munson Army Health Center. “We actually want that liquid in your system—it makes your veins easier to find and lowers the chances of you feeling lightheaded.”
Unlike food, juice, flavored coffee and soda, plain water won’t change your blood sugar, cholesterol, or other values your provider is measuring.
Patients are often asked to fast before certain lab tests because fasting gives the lab a “clean baseline” so your provider can compare results over time.
When you come in dehydrated, your veins may be harder to access, which can lead to multiple attempts at drawing blood.
“Skipping water can increase your risk of dizziness or even passing out,” explained Bennett. “Something as simple as sipping water before your appointment can make your blood draw faster, smoother, and safer.”
If you’re unsure about your fasting instructions, check with your provider beforehand. Otherwise, bring a bottle of water and drink as usual before your lab visit—your body will thank you.