Hematology is a branch of medicine that studies the structure and functions of the blood system and hematopoietic organs, the causes and mechanisms of the development of blood diseases, using various methods for their diagnosis, treatment and prevention. Blood diseases are conventionally divided into non-malignant and malignant (oncohematology). The main groups of non-malignant diseases are: anemia of various nature, leukocyte and platelet diseases, hemorrhagic diseases, vasculitis, reactive lymphadenopathy, leukemoid reactions. Malignant diseases of the blood or hemoblastosis include acute leukemia, chronic myeloid leukemia, lymphomas and histiocytosis.

It has now become apparent that hematology is one of the most rapidly developing medical specialties. If about 20 years ago there were voices calling into question the right of hematology to be considered a separate area of ​​medicine, now the successes achieved by practical and experimental hematology allow, without exaggeration, to call this industry one of the most advanced.

The major role played in this achievement of the fundamental hematological science. Studies of cytogenetics, molecular and cellular biologists on the model of oncohematological diseases allowed not only to characterize individual nosological forms of neoplastic blood diseases, but also determined the most important regularities of carcinogenesis in general.

The successes of modern practical hematology are largely based on the latest developments in theoretical hematology. The methods of immunophenotyping, classical cytogenetics and molecular genetics have become the standard for examining a hematological patient.