How important is the correct identification of the different blood cell types?

The blood forming cells can follow different development pathways, called ‘cell lines’. The main examples are Myeloid, Erythroid and Lymphoid. For example the first cell of the myeloid series is the Myeloblast (Blast cell), and as these cells develop and divide they differentiate into the distinct functional myeloid cells such as Neutrophils, Eosinophils and Basophils. Other mature cells such as Monocytes, Lymphocytes and Red cells come from the other cell lines.

Acute myeloid leukemia (AML) is a cancer of the myeloid line of blood cells, characterized by the rapid growth of abnormal white blood cells that accumulate in
the bone marrow and interfere with the production of normal blood cells. AML is the most common acute leukemia affecting adults, and its incidence increases with age. Patients with AML frequently have too many myeloblasts (often just called blasts), which are immature blood-forming cells that are not normally found in the blood. Therefore, a correct identification of these immature blasts on the blood is extremely important on the diagnosis of this disease.

Haematologists are highly skilled in the identification of the many different blood cell types in humans and in the animals used for medical research. Blood films from rat and mouse commonly show leukaemia which is a common disease of old age in these animals. Blood films from these animals often show immature and sometimes abnormal Blast cells, for which a clear, define image is critical for cell identification.

These images are from a blood film made from an EDTA blood sample taken from a leukaemic rat stained with the a standard May-Grunwald Giemsa stain. Leukaemic immature blast cells, with excellent definition of the granules and nucleoli, are easily identified.