How is MDS diagnosed?
MDS is diagnosed using information gathered from a number of different tests. These include a physical examination, blood tests, a bone marrow biopsy, x-rays and other more specialised tests.
Full blood count
The first step in the diagnosis is a simple blood test called a full blood count (FBC) or complete blood count (CBC). This involves a sample of blood from a vein in your arm being sent to the laboratory for investigation. Most people with MDS have a low red cell and platelet count. Many of the white blood cells may be abnormal leukemic blast cells and the presence of these blast cells suggests you have MDS.
Bone marrow examination
If the results of your blood tests suggest that you might have MDS, a bone marrow biopsy may be required to help confirm the diagnosis. A bone marrow biopsy involves taking a sample of bone marrow, usually from the back of the hip bone and sending it to the laboratory for examination under the microscope. The bone marrow biopsy may be done in the haematologist’s rooms, clinic or day procedure centre and is usually performed under local anaesthesia with sedation given either by tablet or through a small drip in your arm.
The sample of bone marrow is examined in the laboratory to determine the number and type of cells present and the amount of haemopoiesis (blood forming) activity taking place there. Although the blood counts are low, in the majority of cases of MDS the bone marrow is very active but with increased numbers of immature cells that are abnormal in shape, appearance and size. In addition, blood cell production is usually found to be very inefficient; this is referred to as ineffective haematopoiesis. The percentage of blast cells (the abnormal stem cells) seen in the bone marrow (and sometimes in the blood) gives a guide to the severity of the MDS.
The results of this bone marrow test may take a few days to be finalised.
Once the diagnosis of MDS is made, blood and bone marrow cells are examined further using special laboratory tests. These include immunophenotyping and cytogenetic tests. These tests provide more information about the exact type of disease you have, the likely course of your disease and the best way to treat it.
These may be conducted to provide information on your general health and how your vital organs are functioning. These include a combination of further blood tests and imaging tests (x-rays, scans and ECG). These results will provide a baseline of your disease and general health which will be compared with later results to assess how well you are progressing and responding to treatment.