Physical examinations and lab tests are used to diagnose MDS. Most people who have MDS are diagnosed with primary MDS.
Your doctor needs to test your blood to make a diagnosis. Your blood is sent to a lab for a complete blood count (CBC), which reveals the number of red cells, white cells and platelets in your blood. A low red cell count means that you have anemia. If you have anemia, your doctor examines your red cells to find out whether your condition is caused by MDS or:
- low iron, folate or B12
- another type of cancer
- another condition that leads to a rapid breakdown of red cells
Bone Marrow Tests
If your blood test doesn't reveal your anemia's cause, your doctor or oncologist (cancer specialist) will test your bone marrow. Bone marrow testing involves two steps usually performed at the same time in a doctor's office or a hospital:
- a bone marrow aspiration to remove a liquid marrow sample
- a bone marrow biopsy to remove a small amount of bone filled with marrow
Lab Tests to Confirm a Diagnosis
After your doctor takes samples of your blood and bone marrow, he or she may work with a hematopathologist to look for certain changes in your chromosomes, especially if your doctor can't confirm a diagnosis. A hematopathologist is a specialist who studies blood cell diseases by examining samples of blood and marrow cells and other tissues. He or she also makes sure that other causes of anemia and low blood cell counts aren't present.
When examining your blood and bone marrow cells, your doctor diagnoses MDS if he or she finds at least one of the following factors:
- Blasts make up more than 5 percent of marrow cells.
- Cytogenetic abnormalities (damage to DNA in chromosomes) are identified. The most common MDS cytogenetic abnormalities involve:
- a loss (deletion) of the long arm (q) of one of the two chromosomes 5, indicated as "del(5q)" or "5q-"; chromosomes 7, (del[7q] or 7q-); or chromosomes 20, (del[20q] or 20q-)
- an extra copy of chromosome 8, resulting in three copies instead of the normal two (called trisomy 8)
- a missing chromosome 5 or 7 (abbreviated as -5 or -7)
- The marrow's structure or form shows abnormal changes, a condition called dysplasia.
The hematopathologist may use cytogenetic analysis to examine your cells and identify certain changes in chromosomes and genes that can indicate MDS. Fluorescence in situ hybridization (FISH) is an extra sensitive test that can detect chromosome changes. It's also used to identify certain types of MDS.
If you're diagnosed with MDS, you may need to undergo more blood and bone marrow tests before, during or after treatment to identify the type of MDS you have and to check how you're responding to therapy.
Since MDS can be a difficult disease to diagnose, you may want to get a second medical opinion by an experienced hematopathologist before you begin treatment.