Updated 25 Mar 2020

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MDS may be diagnosed at any age but it is very rare in children and young adults. The cause of MDS remains largely unknown, although there are many research groups around the world who are trying to improve our understanding of why it occurs and in whom.

You’ll have a number of tests to confirm your diagnosis. It’s important that you understand your diagnosis – it might be a good idea to ask your consultant to write it down so you can use it if you’re looking for more information or support, or if you need to tell other people about it.

Signs and symptoms

Anaemia is the most commonly experienced symptom in MDS. About eight in 10 patients have anaemia, while about two in 10 present to their doctor with infections or bleeding. 

Anaemia is due to a lack of red cells (also referred to as a low haemoglobin), which may lead to fatigue and shortness of breath even on light exertion. 

When your platelet count is low, you can suffer from easy bruising and bleeding. This can sometimes show itself as a rash on your skin. These are tiny bleedings under the skin called petechiae and often appear where clothes are tight fitted like around the ankles or waist. Nose or gum bleeds can also be a sign of a low platelet count.

Recurrent and persistent infections are another common symptom of MDS due to low white cell counts. 

Some MDS patients have no signs or symptoms and are diagnosed by chance as a result of a routine blood test.


Waiting for your test results may be an anxious time. Talk to your family and friends, or contact patient support organisations. They can help put you in touch with other patients over the phone, in person or through online forums.

Full blood count

Low blood counts are picked up by a simple test called a full blood count (FBC). The laboratory performing the test will then examine the blood cells on a slide (called a blood film) under the microscope. If you are found to have changes on the blood film that suggest MDS, you will usually be referred to a blood specialist (haematologist). It is important to rule out other causes of a low blood count so the doctor will ask general health questions and give you a physical examination. 

Bone marrow test

As MDS is a disease of the bone marrow, a bone marrow test is usually needed to diagnose the condition, or monitor response to treatment.

What does a bone marrow test involve? 

This is usually performed as an outpatient when a small amount of bone and bone marrow are taken, generally from the pelvis (hip bone). The doctor will numb the area with local anaesthetic and a needle is inserted into the bone marrow cavity. A small liquid sample is taken followed by a biopsy. The procedure usually takes around 20-30 minutes, but you should allow an hour of your time. It may be uncomfortable at the time, or later that evening, but simple paracetamol is usually enough to relieve the pain. You may be asked to lie on your back after the procedure for 10 minutes to reduce the risk of bleeding. A small dressing or plaster is applied to the site. 

Why do I have to wait so long for the results? 

Preparing the sample and analysing all the results can take two to three weeks. The bone marrow sample is processed in the laboratory and examined by a doctor under a microscope to look for changes seen in MDS. Additional tests are often requested on the bone marrow sample, which may help to make the diagnosis and provide information about how the disease will behave (prognosis). 

These include cytogenetics (sometimes called a ‘karyotype’), which is the study of the changes in the structure of the chromosomes in the affected cells. It is important to understand that these chromosome changes occur at the time the disease develops and are only in the bone marrow cells (so-called acquired changes) and are not passed on to family members (inherited changes). Some centres are now also testing for ‘molecular’ changes but we are still learning what the changes may mean for MDS patients and this will become clearer in the near future.

In most cases of MDS, the typical features are present in the bone marrow and the diagnosis is straightforward. However, unlike most other diseases, there is currently no specific diagnostic test for MDS and so reaching a diagnosis can sometimes be challenging and take a little longer than expected. If there is doubt about whether or not you have MDS, your doctor may decide to monitor your blood counts and repeat the bone marrow test at a later stage.

A bone marrow sample may not be necessary in the case of some patients whose care is unlikely to be affected by the result – for example, if the patient is not fit or suitable for any treatment.

You can read about the experiences of other people who are going through or have been through the same thing on the websites of patient support organisations. It is important at an early stage to get your support and information from recommended and reputable sources, as the internet can present misleading and unvetted facts.

> Find details of the support organisations that we recommend

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