How to prepare for a blood test

Good preparation is the easiest way to get accurate results and avoid having to repeat a test. Most blood tests need no special preparation at all, but a few depend on what you have eaten or done in the last day.

Which tests need fasting?

Tests such as fasting blood sugar and the lipid profile (cholesterol and triglycerides) usually need 8–12 hours without food. The easiest way is to have an early dinner and give your sample the next morning. Many other common tests — CBC, thyroid, HbA1c, vitamin D and B12 — usually do not need fasting. If you are unsure, ask us when you book.

Can I drink water?

Yes. Plain water is fine during fasting and actually helps — being well hydrated makes the sample easier to take. Avoid tea, coffee, milk, juice and chewing gum until after the sample.

Should I take my medicines?

Usually yes. Take your regular medicines unless your doctor has told you otherwise, and tell us what you take, because some medicines can affect certain results. For a post-meal (PP) sugar test, take your diabetes medicine and food as you normally would, then give the sample 2 hours after starting your meal.

The day before

• Avoid alcohol and very heavy or oily meals.
• Avoid intense exercise, which can temporarily change some results.
• Get a normal night's sleep.

What to bring

• Your doctor's prescription, if you have one.
• Previous reports, so results can be compared.
• Wear loose sleeves for a quick, comfortable sample.