MDS Glossary of Terms

Allogeneic stem cell transplant

A procedure where bone marrow stem cells are taken from a genetically matched donor and given to the patient through an intravenous (IV) line. The donor may be related or unrelated.

Stem cell donation: Become a donor


A medical condition in which the red blood cell count or haemoglobin is less than normal. On a normal blood result, RBC will show as approx:
Red Blood Count (RBC) Males: 4.5-6.5; Females 3.8-5.8 - 1012/l

Blast cell

An abnormal (dysplastic), immature blood cell found in the bone marrow or peripheral blood. As they are not mature, these cells are unable to fulfil their intended function. AML develops from these blast cells.

The picture shows what a blast cell looks like under the microscope. The red arrow and yellow arrow point to the presence of blasts, i.e. abnormal blood cells

Blood transfusion

A procedure in which whole blood or one of its components is given to a person through an intravenous (IV) line into the bloodstream. A red blood cell transfusion or a platelet transfusion can help some patients with low blood counts.

When is a blood transfusion needed? Read the article

Bone marrow

The soft blood-forming tissue that fills the cavities of bones and contains fat, immature and mature blood cells, including white blood cells, red blood cells, and platelets.

What does my bone marrow do? Download PDF


Therapy for cancer using chemicals that stop the growth of cells.

Clinical trial

A medical research study involving patients with the aim of improving treatments and their side effects. You will always be informed if your treatment is part of a trial.

List of Current MDS Clinical Trials in the UK


The study of chromosomes (DNA), the part of the cell that contains genetic information. Some cytogenetic abnormalities are linked to different forms of myelodysplastic syndromes (MDS).


Extreme tiredness, which is not alleviated by sleep or rest. Fatigue can be acute and come on suddenly or it can be chronic and persistent.

How to deal with fatigue? Download the factsheet

Full blood count or FBC

A blood test that counts the number of different blood cells.


The study of genes and their functions, which is increasingly important to refine the prognosis of the various sub-types of MDS. In future this information may also help to personalise MDS treatments.


A protein in the red blood cells. Haemoglobin picks up oxygen in the lungs and brings it to cells in all parts of the body.

Normal counts are approx: Haemoglobin (Hb) Males 130-180; Females 115-165 g/l

The following video shows why haemoglobin counts can be low on MDS patients and explains what each type of blood cell does:


A condition in which the number of neutrophils (a type of white blood cell) in the bloodstream is decreased.


A type of white blood cell that helps fight infection.


A disc-shaped element in the blood that assists in blood clotting. During normal blood clotting, the platelets clump together (aggregate). Although platelets are often classed as blood cells, they are actually fragments of large bone marrow cells (megakaryocytes).

Platelet count

A normal platelet count in a healthy individual is between 150,000 and 450,000 per microlitre of blood. In general, low platelet counts increase bleeding risks.
Normal Platelet Count (PLT) 150-450 - 109/l

Stem cells

Cells that have the potential to develop into many different or specialised cell types.

White blood cell

One of the cells the body makes to help fight infections. There are several types of white blood cells. The two most common types are the lymphocytes and neutrophils.

Normal White Cell Count (WBC) 4-11 - 109/l

Myelodysplastic Syndromes Patients' Stories

Many MDS patients have shared with us their stories and photos, in the hope that fellow patients will find it helpful to read how they have learned to live with MDS.

Read the stories

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