Blood Tests
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Overview
Blood tests are the most common diagnostic tool in medicine. From a simple blood count to specialised hormone and genetic panels, the laboratory at St. Stephen’s Hospital handles the full range, with samples processed in our laboratory department on the same campus.
Reports are reviewed by qualified doctors and uploaded to the patient portal, usually on the same day.
What is this test?
A blood test involves taking a small sample of blood — typically from a vein in the arm. Depending on the test, the sample is collected into different tubes (different coloured caps for different tests) and processed in the laboratory.
Some tests use a fingerprick (such as point-of-care blood sugar). Most use a venous sample.
Why your doctor may order it
- Routine health check-ups
- Diagnosis of suspected disease — infections, anaemia, diabetes, thyroid, liver and kidney conditions
- Monitoring chronic conditions
- Before surgery or before starting certain medications
- Investigating symptoms — fatigue, weight loss, fever, weakness
- Pregnancy and pre-pregnancy assessment
- Cancer screening and monitoring
How long does it take?
The blood draw itself is 2 to 5 minutes. Including registration and waiting, total time is usually2-3 hours. A 24-hour or timed collection takes longer to set up.
How to prepare
- Fasting depends on the test — examples below:
- Fasting glucose, lipid profile: fast 10 to 12 hours.
- HbA1c, CBC, thyroid: no fasting needed.
- Iron studies: avoid iron supplements for 24 hours.
- Hormones (cortisol, testosterone): timing matters — morning samples are usual.
- Tell us about all medications and supplements — many affect blood values.
- Stay well-hydrated in the day before — well-hydrated veins are easier to draw from.
- Bring your prescription, ID, and any previous reports for comparison.
What to expect during the test
You sit comfortably while the phlebotomist cleans the inside of your elbow, tightens a band above it, and draws a sample using a thin needle. The needle is in for a few seconds.
Most people feel a brief sting. After the draw, you press a cotton wool ball on the site for a minute, and a small bandage is applied.
After the test
- Resume normal activities and eating immediately (especially if you were fasting).
- A small bruise is occasionally seen and settles in a few days.
- Reports are typically available the same day and are uploaded to the patient portal.
- Share the report with your treating doctor for interpretation.
Do's and Don'ts
- Follow the fasting instructions for your specific test.
- Drink plenty of plain water the day before.
- Tell us about all medications, including supplements and herbal products.
- Bring previous reports for trend comparison.
- Tell the phlebotomist if you've fainted during blood draws before — we can position you lying down.
- Don't break your fast if the test requires it.
- Don't take supplements (biotin, iron) just before relevant tests.
- Don't worry about a one-off mildly abnormal result — repeat testing and a doctor's review are the right next steps.
- Don't self-interpret reports — small variations are normal, and patterns matter more than individual numbers.
- Don't insist on excessive testing for reassurance — too many tests can produce confusing results.
Understanding your results
Most blood tests come with reference ranges next to each value. “In range” generally means normal for the population, but “normal” doesn’t always mean optimal for you — and vice versa.
Your doctor interprets results in the context of your symptoms, history, and other findings. If you are unsure, ask. We would rather you ask than misinterpret.
Frequently asked questions
Most routine blood tests need 5 to 20 ml total — a few teaspoons. Even for many tests, the total amount taken is well within what your body easily replaces.
Yes. Tell us in advance. We can lie you down, distract you, and use the smallest needle possible. Most needle phobia gets easier once you know what to expect.
Different tests need blood mixed with different chemicals (anticoagulants, gel for clotting, etc.). Hence the different coloured caps. It looks like a lot — but the total volume is small.
Yes, with your written authorisation and a copy of your ID and payment receipt. We do not release reports without identification.