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Tissue typing is a set of tests that are done with your blood and saliva. You might have it if your doctors think that you need a stem cell or bone marrow transplant 
from someone else (donor transplant). It is to show how closely a possible stem cell or bone marrow donor’s tissue matches your own.
You might also hear this test called other names such as:
- HLA tissue typing
- HLA typing
- Histocompatibility testing
- HLA crossmatching
You usually have one or more of the following tests:
- a blood test
- a swab taken from the inside of your cheek (buccal swab)
- a spit (saliva) sample
What does HLA mean?
HLA stands for human leucocyte antigen. They are proteins that are found on the surface of most cells in your body. HLA proteins are important as they help your immune system figure out which cells in your body are yours and which are not (foreign). If your immune system picks up a foreign cell then it triggers an immune response .
Each person has their own specific set of HLA proteins that they have inherited from each parent. Doctors in the laboratory can check the blood and saliva sample for the HLA proteins (or HLA markers). They check for 10 HLA markers.
The result of this test shows how good the HLA match is between you and the person who might be able to donate their cells. Your doctor wants the best match so there is less chance that your immune system will reject the donor’s blood cells. You might hear them say you have a 10 out of 10 match or a 9 out of 10 match.
Your medical team will talk to you about which members of your family can be tested. This is usually your siblings.
Preparing for your tissue typing test
Blood and mouth swab test:
You can eat and drink normally before your test. Take your medicines as normal.
Saliva sample:
You should not eat, drink, smoke or chew gum for 30 minutes before giving this sample.
What happens?
Blood test:
You sit or lie down to have the test.
A doctor, nurse or phlebotomist (person specialised in taking blood) chooses the best vein to use. This is usually from your arm or hand. Let them know if you are afraid of needles, get unwell with the sight of blood or are allergic to plasters or latex.
They put a tight band (tourniquet) around your arm above the area where they take the sample. You may need to clench your fist to make it easier to find a vein.
They clean your skin and then put a small needle into your vein. Next, they attach a small bottle or syringe to the needle to draw out some blood. They might fill several small bottles.
Once they have all the samples, they release the band around your arm. They then take the needle out and put pressure on the area with a cotton wool ball or small piece of gauze for a few minutes. This helps to stop bleeding and bruising.
Look away when they’re taking the blood if you prefer. Tell your doctor, nurse or phlebotomist if you feel unwell.
Mouth swab test:
The swab looks like a very long cotton bud. You or your nurse can do it. If doing it yourself it might be best to do it by looking in the mirror.
Your nurse might ask you to sit upright in a chair or if you prefer you can stand.
The nurse or you will then remove the swab from the packet. Do not allow the tip of the swab to touch anywhere else apart from the inside of your cheek. You or the nurse then rubs the swab on the inside of your cheek for several seconds. The swab is then placed into the tube to be sent to the laboratory.
Saliva sample:
You sit upright in a chair or if you prefer you can stand. You then spit the saliva into the container. This then sent on to the laboratory for testing.
Getting your results
Ask when to expect your results and how you will receive them.
Contact your specialist nurse if you have any questions about tissue typing or bone marrow transplants.
Possible risks
These are very safe tests. There are possible risks if you are having a blood test. These might include:
- bleeding and bruising – pressing hard when the needle is removed can help to stop it
- pain – this is normally mild and can last for a few minutes
- swelling (oedema) – ask your nurse, doctor or phlebotomist to avoid an arm that is swollen or has a risk of swelling
- feeling faint or fainting – tell the person doing your blood test if you’re feeling lightheaded or dizzy at any time
- infection – this is very rare
