Hematologic Malignancies Program

Myelodysplastic Syndromes (MDS)

Diagnosing MDS

If signs and symptoms suggest a patient may have myelodysplastic syndrome or myeloproliferative disorder, the doctors will need to examine cells from the patient's blood and bone marrow in order to be certain of this diagnosis.

Tests include:

Blood cell counts and blood cell examination: Blood cells from MDS patients may also have certain abnormalities of their size, shape or other features that can be recognized under the microscope. Even though these findings suggest a myelodysplastic syndrome, these conditions cannot be diagnosed for sure without examining a sample of bone marrow cells.

Bone marrow biopsy and aspiration: Bone marrow aspiration involves removing a few drops of bone marrow. During a biopsy, a small cylindrical piece of bone and bone marrow is removed. Both samples generally are taken at the same time from the back of the hipbone. These tests are used first for diagnosis and classification may be done again later to tell if the myelodysplastic syndrome is responding to therapy or is transforming into an acute leukemia.

Cytochemistry: After cells from a circulating blood sample or bone marrow sample are placed on glass microscope slides, they are exposed to stains (dyes) that are attracted to certain chemicals present in only some types of myelodysplastic syndrome or myeloproliferative disorder cells.

Flow cytometry: This technique is sometimes used to examine the cells from bone marrow, and blood samples, and can determine the exact type of a myelodysplastic syndrome or leukemia. A sample of cells is treated with special antibodies and passed in front of a laser beam. Each antibody sticks only to certain types of myelodysplastic syndrome or myeloproliferative disorder cells. If the sample contains those cells, the laser will cause them to give off light. The light is detected by the instrument and the cells are counted by a computer.

Immunocytochemistry: As in flow cytometry, cells from the bone marrow aspiration or biopsy sample are treated with special antibodies. Instead of using a laser and computer for analysis, the sample is treated so that certain types of cells change color. The color change can be seen only under a microscope. Like flow cytometry, it is helpful in distinguishing different types of myelodysplastic syndromes or leukemia from one another and from other diseases.

Cytogenetics: Normal human cells contain 46 chromosomes. They are composed of DNA and control cell growth and metabolism. In some cases of myelodysplastic syndrome one or more chromosomes or parts of chromosomes may be missing. Or MDS cells may have too many copies of one or more chromosomes or portions of chromosomes may trade places with each other. The results of this testing describe which chromosome changes are present.

Molecular genetic studies: Tests of myelodysplastic syndrome cells' DNA can find most of the translocations that are visible under a microscope in cytogenetic tests. DNA tests can also find some translocations involving parts of chromosomes too small to be seen with usual cytogenetic testing under a microscope.

This page was last updated on: August 6, 2008.