🚫 Fasting Required ⏱ 5–10 minutes

🩸 How to Prepare for a
Fasting Blood Test

A fasting blood test measures glucose, cholesterol, triglycerides, and liver or kidney markers in their baseline state — without the influence of recent food. Correct preparation ensures accurate results and prevents unnecessary repeat tests.

✅ Preparation Steps

Fast for 8–12 hours before your test

Do not eat any food from midnight the night before (or 8 hours before your appointment, whichever comes first). The fast must include no snacks, chewing gum, or sweets — anything the stomach digests will alter your blood glucose and lipid readings.

Water is allowed — and encouraged

Plain water is not only permitted but recommended. Staying hydrated makes veins easier to locate and reduces the chance of a difficult blood draw. Drink 2–3 glasses of water in the morning before your appointment.

Avoid alcohol for at least 24 hours

Alcohol raises triglycerides and liver enzymes (ALT, GGT) for up to 24–48 hours after drinking. Even one drink the night before can produce a falsely elevated liver function result. Aim for 48 hours alcohol-free before a full lipid panel.

Continue your regular medications — unless told otherwise

Most regular medications (blood pressure drugs, statins, thyroid tablets) should be taken as normal on the day of your test. The one exception: if you are having a fasting glucose specifically to check how your diabetes medication is working, your doctor may ask you to take it after the test. When in doubt, call us before your appointment.

Avoid strenuous exercise the morning of the test

Vigorous exercise raises creatine kinase (CK), potassium, and glucose temporarily. Take it easy on the morning of your appointment — a gentle walk is fine.

Arrive in the morning

Morning appointments (before 10 am) are ideal for fasting tests. You will have naturally fasted through the night, and results will be available faster. Arriving late in the day after a 12-hour fast while hungry and tired makes the experience harder — plan for an early slot.

🎒 What to Bring

📋 Your doctor's request form or test prescription (if you have one)
📋 Any previous blood results for comparison
📋 A list of all medications and supplements you are currently taking
📋 Valid ID (for patient registration)
📋 A small snack to eat immediately after the blood draw — you will be hungry!

🔬 What to Expect

Arrival (0 min)

Check in at reception and confirm which tests are being requested. Our phlebotomist will review your preparation briefly.

Blood draw (2–5 min)

A tourniquet is applied above the elbow. A small needle is inserted into a vein (usually the antecubital fossa — the inner elbow). Most patients describe it as a brief sharp pinch. Usually 2–4 tubes of blood are collected, depending on the tests ordered.

After the draw (2 min)

Pressure is applied for 1–2 minutes. A plaster is placed on the site. You can eat your snack immediately and resume normal activities.

Results

Most results are ready within 2–6 hours. Glucose and lipid results are often available the same day. Some specialised markers (e.g., HbA1c, hormone panels) may take 24 hours. We will notify you by call or message when results are ready.

🏠 After Your Test

Eat your snack or a proper meal as soon as the blood draw is complete — do not delay if you feel lightheaded.
If you feel dizzy after the draw, sit for 5–10 minutes before leaving. Inform our staff immediately.
The plaster can be removed after 30 minutes. A small bruise at the site is normal and usually fades within 3 days.
Once your results are ready, book a follow-up with your doctor to interpret them — do not interpret reference ranges alone without clinical context.
If you are on a statin or blood pressure medication and your first result was abnormal, your doctor will advise whether to recheck after a medication change.

Frequently Asked Questions

Can I drink coffee or tea during the fast?

No — not even black coffee or tea without sugar. Both stimulate liver glucose output and insulin release, altering fasting glucose results. Herbal tea (plain) is unlikely to cause significant changes but is best avoided to be safe. Stick to plain water only during the fasting period.

What if I accidentally eat something?

Be honest with our phlebotomist on arrival. Accidentally eating does not mean your appointment is wasted — your doctor may still want a random (non-fasting) glucose and full blood count that day, and schedule the fasting tests for another morning. Please do not pretend you fasted when you did not, as this would lead to incorrect result interpretation.

Can I take my blood pressure medications before a fasting test?

Yes — most antihypertensives, cholesterol medications, thyroid tablets, and antibiotics should be taken as normal. The exceptions are diabetes medications (particularly insulin and sulphonylureas like glibenclamide) where your doctor may advise taking them after the test. Always confirm with your prescribing doctor if in doubt.

How long before I get my results?

Glucose, full blood count, and basic chemistry panels are usually ready the same day, within 2–6 hours of the blood draw. HbA1c, lipid panels, liver function, and kidney function are typically available within 24 hours. We will call or message you when your results are ready to collect or discuss.

🩸 How to Prepare for aFasting Blood Test