Myelodysplastic Syndromes - MDS: Diagnosis

Approved by the Cancer.Net Editorial Board, 05/2023

ON THIS PAGE: You will find a list of common tests, procedures, and scans that doctors use to find the cause of a medical problem. Use the menu to see other pages.

Doctors use many tests to find, or diagnose, cancer. They also do tests to learn the extent of the disease. Doctors may also do tests to learn which treatments could work best.

For most types of cancer, a biopsy is the only sure way for the doctor to know if an area of the body has cancer. In a biopsy, the doctor takes a small sample of tissue for testing in a laboratory. If a biopsy is not possible, the doctor may suggest other tests that will help make a diagnosis.

How are myelodysplastic syndromes (MDS) diagnosed?

There are different tests used for diagnosing MDS. Not all tests listed below will be used for every person. Your doctor may consider these factors when choosing a diagnostic test:

  • The type of cancer suspected

  • Your signs and symptoms

  • Your age and general health

  • The results of earlier medical tests

In addition to a physical examination, the following tests may be used to diagnose MDS:

  • Blood tests. A complete blood count, or CBC, measures the numbers of red blood cells, white blood cells, and platelets. Blood tests may also be done to rule out other conditions that can cause symptoms similar to MDS, such as low levels of vitamin B120, iron folate, copper, and thyroid problems.

  • Peripheral (circulating) blood smears. A drop of blood is placed on a glass microscope slide, smeared into a thin film, and placed under a microscope for examination. The percentages of the different types of cells are counted. Also, the appearance of cells under the microscope, called cell morphology, is looked at to find out if or how the cells are different from healthy cells.

  • Bone marrow aspiration and biopsy. These 2 procedures are done to examine the bone marrow. Bone marrow has both a solid and liquid part. A bone marrow aspiration removes a sample of the fluid with a needle. A bone marrow biopsy is the removal of a small amount of solid tissue using a hollow needle. These procedures are often done at the same time and may be called a bone marrow examination.

    A pathologist then analyzes the sample(s) to determine the percentage of red blood cells, white blood cells, platelets, and blasts. A pathologist is a doctor who specializes in interpreting laboratory tests and evaluating cells, tissues, and organs to diagnose disease. A common site for the bone marrow aspiration and biopsy is the pelvic bone, which is located in the lower back by the hip. Doctors generally give a type of medication called anesthesia beforehand to numb the area. Anesthesia is medication that blocks the awareness of pain. Stronger types of anesthesia can also be used to lessen the pain. The appearance of the bone marrow tissue, along with blood cell counts and chromosomal analysis (see below), is needed to confirm a diagnosis of MDS.

  • Molecular testing. Your doctor may recommend running laboratory tests on a bone marrow sample to identify mutations in specific genes, abnormal proteins, and other factors unique to MDS. Results of these tests can help better classify the MDS, understand if the MDS is familial (also known as germline predisposition), determine your treatment options, and/or find out how treatment is working.

  • Cytogenetic (chromosomal) analysis. Looking at the chromosomes of the cells in the blood and bone marrow shows specific abnormalities that help doctors tell the difference between MDS and other blood disorders. About 50% of people with MDS have 1 or more chromosomal abnormalities in their cancer cells, regardless of the subtype. Primary MDS often has a single chromosomal abnormality. Secondary MDS that occurs after prior exposure to chemotherapy or radiation often has many or complex chromosomal changes. The most common abnormalities affect chromosomes 5, 7, 8, 11, 12, 17, and 20.

  • Immunophenotyping. Immunophenotyping is the examination of antigens, a specific type of protein, on the surface of the MDS cells. Immunophenotyping can help identify the type of MDS. This test is most often done with a flow cytometer.

  • Genetic profiling using Next Generation Sequencing (NGS) of DNA. Most MDS cells have mutations in one or more genes that control the growth of cancer cells as well as resistance to treatment. The abnormal gene products that come from these mutations can sometimes be targeted with very specific drugs.

After diagnostic tests are done, your doctor will review all of the results with you. If the diagnosis is MDS, these results also help the doctor describe the disease and determine the subtype and classification.

The next section in this guide is Subtypes and Classification. It explains the system doctors use to describe MDS. Use the menu to choose a different section to read in this guide.