Do you need to fast before a blood test?

Some blood tests need an empty stomach and most do not. A quick guide to getting ready for your lab visit.

  • 7 October 2026
  • 1 min read

Fasting means not eating or drinking anything except plain water for a set time before your blood is taken. It matters for some tests because food changes the levels being measured.

Tests that usually need fasting

  • Fasting blood sugar
  • Lipid profile (cholesterol)

These usually need 8 to 12 hours without food. Many other tests, such as a complete blood count, do not need fasting at all.

Tips for the day

  • Plain water is fine and helps make the blood draw easier.
  • Bring your doctor's test request and a list of your medicines.
  • If you take medicine for diabetes, ask your doctor before fasting.

If you are not sure whether your test needs fasting, call the clinic before your visit.

This article is general information, not a diagnosis. Please see a doctor about your own symptoms.

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