Home Blood Tests: How to Prepare and What to Expect

Why Tests Are Done at Home

Home sample collection is useful for patients who are bed-bound, frail, recovering after discharge, or unable to travel easily. The tests themselves are the same as those done at a laboratory — only the place where the blood is taken is different. The sample is labelled, stored and transported to the laboratory for analysis.

Before the Test

Check the request

Have the written or electronic test request from the doctor available. It shows exactly which tests are needed and prevents omissions or unnecessary extra tests. If you are arranging tests without a request, ask a doctor which tests are appropriate — ordering broad panels "just to check" often produces borderline results that cause worry without helping.

Fasting

Only a few tests require fasting. Most common blood tests, such as a full blood count, kidney function and electrolytes, do not. Our guide on which blood tests actually require fasting explains this in more detail. If fasting is needed, drinking plain water is usually allowed and helps make the blood easier to draw.

Medicines

In most cases, usual medicines should be taken as normal. There are some exceptions: for certain tests that measure the level of a medicine in the blood, the timing of the sample in relation to the dose matters, and some thyroid tests are affected by when thyroid medicine was taken. People with diabetes who are asked to fast need individual advice about their diabetes medicines. Ask the doctor who requested the test before withholding or delaying any medicine.

Timing

Some tests are best taken at a particular time — for example, early in the morning, or a certain number of hours after a medicine dose. If the request mentions a specific time, arrange the collection accordingly.

Preparing the Patient

• Unless the patient is fasting under instructions that exclude water, encourage them to drink some water beforehand. Being well hydrated makes veins easier to find.
• Keep the patient warm; cold arms make veins harder to see.
• Wear loose clothing with sleeves that can be rolled up easily.
• Tell the person collecting the sample if the patient has had a mastectomy, a dialysis fistula, a stroke affecting one arm, or a drip in one arm, as that arm may need to be avoided.
• Mention any history of fainting during blood tests, so the patient can lie down during the procedure.
• Have identification details and, if relevant, previous reports available.

During Collection

The person collecting the sample should confirm the patient's identity, clean the skin, apply a tourniquet briefly, take the blood with a sterile single-use needle, and label the tubes in front of the patient. Correct labelling is essential so the results are matched to the right person.

It is reasonable to ask the collector to confirm which tests are being taken and when the results are expected.

After the Test

• Press firmly on the puncture site for a few minutes, keeping the arm straight rather than bent, to reduce bruising.
• Patients taking blood thinners may need to press for longer.
• A small bruise is common and usually fades within days.
• If the patient was fasting, they can usually eat and take any delayed medicines afterwards, as advised by their doctor.

Seek advice if there is continued bleeding despite pressure, increasing swelling of the arm, or signs of infection at the site such as spreading redness or warmth.

Receiving and Using the Results

Results are most useful when they are reviewed by the doctor who requested them, in the context of the patient's symptoms, examination and previous results. A result slightly outside the printed reference range is common and does not necessarily indicate a problem. Our guide on understanding common blood tests explains why.

Keep copies of reports together, in date order, so that trends can be seen over time. Sineth Hospitals' mobile lab page describes the home sample collection service.

Related Guides

• Fasting Blood Tests: Which Tests Actually Require Fasting?
• Understanding Common Blood Tests Ordered During Home Medical Care
• When Repeat Blood Tests Are Needed During Recovery at Home
• How to Prepare for a Doctor Home Visit