You’ll have a set of tests to confirm whether you have APL or not. At any time, you can ask your healthcare team to tell you why you’re having a certain test and what the results mean.
Initial tests to diagnose APL
Full blood count
A full blood count (FBC) measures the number of each type of cell in the blood: red cells, white cells and platelets. You may be sent for this test by your GP as part of a routine check-up. Other patients might have this test when they’re in hospital for something else.
If your FBC shows that you may have APL, you’ll need to go to hospital for more tests. If you’re diagnosed with APL, you’ll have regular FBCs to monitor your condition during and after treatment.
Bone marrow aspirate (biopsy)
Your doctor will also take a bone marrow sample to see how your blood is working inside your bone marrow.
A small sample of your bone marrow is taken from the hip bone using a needle (an aspirate). Your doctors will then look at the bone marrow sample under a microscope to assess for any disease.
You can have local anaesthetic or mild sedation for this procedure. It’s usually quite quick but will be uncomfortable while the sample is being taken from the marrow; you can take painkillers if you need to.
You will need to stay in hospital even before your diagnosis is confirmed. This is because if your doctor suspects you have APL, you will need to start treatment soon due to the risk of bleeding, and will be kept in hospital throughout the early stages of treatment.
> Find out more information on tests from a website supported by the Department of Health
Tests to confirm diagnosis
Although the result of your blood count test and bone marrow aspirate may indicate that you have APL, your doctor will need to do the following tests on your samples in order to make a formal laboratory diagnosis of APL.
All kinds of cancer, including blood cancer, involve changes in genes in the affected cells. The study of these changes is called cytogenetics or molecular genetics. This isn’t the same thing as a faulty gene that you inherit from a family member which causes cancer.
The cytogenetics lab uses your bone marrow sample to look for changes in the chromosomes in your cells. FISH testing is a technique used in order to do this (FISH stands for fluorescence in situ hybridisation).
This test is done to detect the PML/RARA gene, which is unique to APL. Finding this gene confirms a diagnosis of APL, and means that you do not have another type of AML.
Your doctor will also check your bone marrow sample for the PML/RARA gene using a test called the polymerase chain reaction (PCR). This test, along with the cytogenetics test, is done to confirm your diagnosis.
The PCR test is also done when you’re having follow-up appointments after your treatment. This is to see if all the APL cells have gone and to monitor for any signs of the disease returning (relapse).
Your doctors will carry out a number of other tests. These will give you and your healthcare team more information on the cancer and your fitness for treatment.
Immunophenotype analysis looks at the pattern of proteins on leukaemia cells taken from a blood or bone marrow sample. It is used as part of the process of diagnosing APL.
Blood clotting system tests
APL can interfere with the blood clotting system, so it can increase the risk of bleeding and blood clots. For this reason, clotting tests are particularly important and you’ll have them regularly in the early phases of your treatment.
General health tests
When you’re diagnosed with APL, you’ll have a general health assessment. This will help your healthcare team to assess how you’re likely to cope with side effects from treatment.
You’ll have a range of tests to check your general health, including your heart, liver and kidney function, and infection screening for HIV and hepatitis.
A large majority of patients with APL will have the PML/RARA gene, which will mean they’ll be likely to respond to the standard drugs used in the treatment of APL.
There are also a number of rarer types of APL (approximately 1 case in 100 is PML/RARA negative, meaning it doesn’t feature the PML/RARA gene). Standard treatment may not be as effective against these types. If you’re diagnosed with one of these rare forms, your doctor will talk to you about which alternative course of treatment might be best for you.