Detection of possible pathological elements present in the peripheral blood can be increased by preparing a concentrated fraction of nucleated blood elements (“buffy coat”). When only a small number of immature cells or abnormal cellular elements are present, they cannot be detected on usual blood smear, leukocyte concentrate can be helpful in identifying them.

Recommendations:

– pancytopenia without apparent cause: detection of abnormal or immature cells;

– leukopenic leukemia: detection of blasts;

– leukoerythroblastic panel: identification of myeloid precursors, erythroblasts, megakaryocyte fragments.

–  macrocytic anemia (megaloblastic): identification of megaloblasts  (nucleated erythroid precursors) and hypersegmented granulocyte;

– multiple myeloma: the presence of plasma.

– hairy cell leukemia: identification of hairy cells.

– When circulating tumor cells are suspected (lymphoma in leukemic phase).

Normal values ​​- absent abnormal cellular elements.

Overt – blades focused on leukocyte blood cells may be present that are not normally in the current leukocyte formula, such as myelocytes, leukocyte concentrate metamyelocytes . On the blades one cannot accurately assess the morphology of red blood cells, and platelets leukocyte formula. Sometimes we see a greater number of monocytes.

However well done leukocyte concentrate smears are representative of the general population of nucleated cells present in blood. In cases of leukopenia can be examined in a short time many more cells than normal smears. Identification of immature cells, abnormal cells, blasts, or other circulating tumor cells circulating nucleated and bacteria or intraleukocyte parasites (unusual organisms such as severe infections with Strongyloides stercoralis in immunosuppressed patients, microfilariae) provides important diagnostic information and can reduce need for other more complex tests.