Blasts

Norm
Not found

Blood
Stained blood smear

Most often, blasts are found in patients with leukemias or MDS syndrome. Up to 5% of blasts can be found in the bone marrow of a healthy individual. During leukemia remission, the number of blasts in the bone marrow decreases to normal or is slightly increased. Leukemia can also exist without blasts in the peripheral blood. Therefore, when unclear leukopenia or pancytopenia is detected, it is necessary to thoroughly examine the patient. Only a bone marrow puncture can confirm or rule out the diagnosis. It can be difficult to identify the type of leukemia based on blast morphology. Additional cytochemical reactions and staining with immunophenotypic (immunofluorescent) markers are used to clarify the type of blasts. Flow cytometry can be used to observe various forms of blast differentiation. It is now proven that all cells younger than blasts appear as mature lymphocytes under a microscope. Immunophenotype can indicate the degree of maturity of a particular “lymphocyte.” Stem cells, from which all blood cell elements develop, are characterized by a CD34⁺ immunophenotype (Blast identification “Cytochemistry”, “FAB leukemia classification”, “Flow cytometry”).

Source | Handbook of Basic Laboratory Tests | Doctor of Medical Sciences Gintaras Zaleskis