Fasting means not eating or drinking anything except plain water for a specific amount of time before your test.
Fasting helps ensure that your blood test results are accurate, especially for tests that are affected by food or beverages (such as glucose, lipids/cholesterol, triglycerides, and some metabolic tests).
What you can do during fasting:
- Drink plain water only (no flavouring, sugar, lemon, or sparkling water).
- Take essential medications, unless your doctor has advised otherwise.
- Continue your normal routine (e.g., walking, light activities) but avoid heavy exercise before your test.
What you must avoid during fasting:
- No food at all.
- No tea, coffee, juice, milk, soft drinks, alcohol, or sports drinks.
- No gum, lozenges, mints, or cigarettes—these can affect results.
- Avoid supplements (vitamins, iron, magnesium, etc.) unless instructed otherwise.
How long do I need to fast?
Most fasting tests require 8–12 hours without food.
Your doctor or pathology request form will specify the required fasting time.
Tips to make fasting easier:
- Book a morning appointment so most of your fasting happens overnight.
- Drink plenty of water before coming in—this helps with blood collection.
- Bring a snack so you can eat as soon as your test is finished.
What if I accidentally ate or drank something?
It's best to tell staff when you arrive. In some cases, the test may still be performed; in others, your doctor may request you return on another day for accurate results.
If your doctor has not specifically instructed you to fast, fasting is not required.
For more details, please refer to our fasting patient information.
