Laboratory diagnosis of acute leukemia – analyzes
A blood test for acute leukemia. Most patients with acute leukemia (OL) at the time of diagnosis of the disease have normochromic normocytic anemia, which is more pronounced in acute myeloblastic leukemia. With the development of hemorrhagic complications, hypochromia may occur due to iron deficiency. The number of peripheral blood leukocytes varies widely (from 1 • 109 / l to 200 • 109 / l), but more often it remains at the subleukemic level and does not exceed 20-30 • 109 / l.
The most pronounced leukocytosis is observed in patients with T-ALL and acute monoblastic leukemia. When calculating the leukocyte formula in 90% of patients with acute leukemia blast cells are detected, the number of which can vary from 1-2 to 100%. In typical cases, there are no intermediate forms of neutrophilic cells between the blasts and mature granulocytes (“leukemic failure”, or hiatus leukaemicus).
In 20% of patients, the number of blast cells exceeds 50 × 109 / l, and in 10% of the blasts in the peripheral blood are absent (pancytopenia and relative lymphocytosis are usually noted). At the level of leukocytes above 100 • 109 / l, the risk of the development of leukostatic complications (neurological disorders, acute respiratory distress syndrome, in men, in addition, priapism) sharply increases.
Thrombocytopenia is detected in the overwhelming number of patients with acute leukemia and is more pronounced in acute myeloblastic leukemia (AML) (in half of the patients the number of platelets is less than 50 • 109 / l). At the same time, in 1–2% of patients thrombocytosis is noted (more than 400 • 109 / l).
In some patients, an increase in prothrombin and partial thromboplastin time may be noted; in acute promyelocytic leukemia, a decrease in fibrinogen level and other signs of DIC are often observed. It should be noted that the development of the syndrome of DIC is possible with any variant of acute leukemia.
Myelogram with acute leukemia. The study of bone marrow aspirate is needed to diagnose and establish a variant of acute leukemia. The number of myelokaryocytes is usually increased, megakaryocytes are absent or their number is reduced. When calculating the myelogram, at least 20% of blasts are detected, constriction of normal hemopoiesis sprouts. To verify the variant of acute leukemia, it is necessary to conduct cytochemical, immunological and cytogenetic studies, the results of which have prognostic significance and allow planning medical tactics.