What to Know Before Fasting for Blood Tests – A Guide from ClearMedica

When your doctor orders blood tests, you may need to fast. Fasting helps make the results more accurate, so it’s important to know what you should and shouldn’t do before the test. At ClearMedica, through our ClearCare membership service, we’re committed to helping patients prepare adequately for their diagnostic tests by offering comprehensive primary care and routine lab testing as part of our affordable monthly plans.

Why Fasting Matters

Fasting before blood tests helps give accurate results
Eating or drinking can alter your blood sugar, fat, and other levels
This may affect test results and require additional follow-ups

How Long Should You Fast?

Standard fasting period: 8–12 hours
If your appointment is at 8 AM, stop eating by 8–10 PM the night before
Basic metabolic panel: 8–12 hours
Lipid panel: 9–12 hours
Glucose tolerance test: 8–10 hours
Iron studies: 12 hours
Always follow your healthcare provider’s instructions

What Can You Drink While Fasting?

Plain water – drink plenty to stay hydrated
Black coffee – no cream, sugar, or artificial sweeteners
Plain tea – without any additives
Avoid juice, soda, sports drinks, flavored water, and anything with calories or artificial sweeteners

ClearCare Makes Blood Testing Simple

ClearCare Core, ClearCare Elite, and ClearCare Max include routine lab tests in monthly membership
Predictable costs with no hidden lab fees
Easy scheduling for fasting blood work through our online portal
Same-day or next-day appointments available
Direct access to healthcare providers who can explain your results

Which Tests Require Fasting?

Blood sugar
Cholesterol
Triglycerides
Metabolic panels
Liver function tests
Iron levels
Ferritin levels
Insulin levels
Tests that usually do not require fasting: CBC, thyroid tests, most hormone tests

The Night Before Your Test

Eat a regular, balanced meal
Take medications as prescribed unless instructed otherwise
Set a reminder for when to stop eating
Stay well-hydrated with water

On the Day of the Test

Continue drinking water
Avoid exercise or strenuous activity
Arrive on time to minimize additional fasting

Essential Preparation Tips

Do not stop medicines unless your doctor instructs you
Most medicines can be taken with a sip of water, but some may need timing adjustments
ClearCare members can schedule with their provider to discuss medication timing and fasting requirements

Special Considerations

Diabetes patients should consult their provider to adjust insulin or medication safely
Pregnant women, elderly patients, and those with chronic conditions may have modified fasting requirements

After Your Test

Resume normal eating and drinking once blood is drawn
A light snack can prevent dizziness or fatigue after long fasting periods
Preparing properly ensures accurate test results and better health choices
ClearCare members benefit from easy lab tests, simple scheduling, and complete primary care
ClearCare makes healthcare affordable and hassle-free, no insurance required

Our service areas include Brandon, Lakeland, and Winter Haven.