Fasting Blood Test: Common Questions

Some blood tests require fasting to get an accurate reading — most commonly blood sugar and lipid profile tests, since eating can temporarily raise glucose and fat levels in the blood. Here are answers to the questions we hear most often.

How long should I fast?

Fasting requirements vary by test — commonly 8 to 12 hours, but always confirm the exact duration for your specific test with our team or your doctor, since it can differ.

Can I drink water before a blood test?

Plain water is generally fine during a fasting period and doesn't count as breaking your fast. What you should avoid is tea, coffee, juice, sugary drinks, and food.

What if I accidentally eat something?

If you eat or drink something other than water during your fasting window, let the phlebotomist or lab know before the sample is collected. It's usually better to reschedule than to submit a sample that won't give an accurate result.

Do all tests need fasting?

No — many common tests, including CBC and thyroid profile, don't require fasting. When you book, our team will confirm exactly which preparation steps apply to your specific test or package.