Myelodysplastic Syndrome Overview

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Early Detection, Diagnosis, and Staging TOPICS

How are myelodysplastic syndromes found?

Sometimes a myelodysplastic syndrome (MDS) is suspected because of abnormal results on blood tests ordered because of some other problem. At this time, though, no special tests are used to look for MDS in people without symptoms.

Tests used to find and classify MDS

If there is any reason to suspect MDS, the doctor will look at cells from your blood and bone marrow to find out if the disease is really there.

Blood cell counts and blood cell exams

The complete blood count (CBC) is a test that measures the different cells in the blood, like red blood cells, white blood cells, and platelets. Patients with MDS will often have changes in the numbers of different blood cell types. Under the microscope the cells may also look different in shape and size. Blood tests can suggest MDS, but the doctor will need to look at a sample of bone marrow cells to be sure.

Bone marrow tests

The procedures to remove samples of bone marrow samples are called bone marrow aspiration and biopsy. Most often, these 2 tests are done at the same time. The bone marrow usually is removed from the back of the hip (pelvic) bone. You lie on a table (either on your side or on your belly) and a large needle is used to suck out bone marrow (the aspiration). Then a different needle is used to remove a small cylinder of bone (the biopsy). The skin and the bone are numbed before the bone marrow is removed. Sometimes medicine to make you sleepy is given as well.

A doctor with special training will look at the bone marrow cells under a microscope to see if they look abnormal. The doctor is also looking to see how many blasts are in the bone marrow. Blasts are very early cells that are made by bone marrow stem cells. Over time, blasts should change (mature) into normal blood cells.

In MDS, the blasts do not mature, so there may be too many blasts and not enough mature cells. Some patients with MDS have more blasts than normal, but if they have more than 20% blasts in the bone marrow they actually have acute leukemia and not MDS.

The bone marrow will also be sent for tests of chromosomes or genes. This is needed to help the doctor learn what kind of MDS is present as well as the patient’s outlook.

For more information about the tests that are used to diagnose MDS, see our document Myelodysplastic Syndromes.


Last Medical Review: 02/27/2014
Last Revised: 04/03/2014