Summary
Background. After more than 100 years since the first attempts to automate blood cell counting, the Complete Blood Count with an Automated Leukocyte Differential, abbreviated as CBC w/ auto-DIFF (CBC), remains one of the most commonly ordered tests worldwide. A significant portion of diseases is related to changes in White Blood Cells and the Leukocyte Differential seen in CBC results. By properly assessing these changes, doctors gather a lot of information about further patient examination, treatment strategy, or disease prognosis. In the authors' opinion, there is a lack of orientational and educational information in Lithuania for general practitioners, medical students, and other medical specialists regarding the role of CBC and other hematological tests in the diagnostic pathway of disease. Therefore, it is necessary to review not only the test results but also the methods by which they are achieved.
Aim of the study. To perform a literature analysis, presenting the main methods of leukocyte testing, the clinical utility of their results, and the differential diagnosis of changes in the total leukocyte count.
Material and methods. A literature search was conducted using free search and several databases: PubMed, ScienceDirect and ResearchGate. The following keywords were used: leukocytes, leukocytosis, complete blood count, hematological analyzers, principles of hematological analyzer operation, leukocytosis algorithm. 57 relevant studies that met the research objectives were selected. Neither a predefined search period nor inclusion protocol were applied to this study.
Conclusions. Despite the increasing amount of new diagnostic methods, CBC remains one of the most clinically significant tests, providing a quick, cost-effective, and informative assessment of a patient's blood. Proper interpretation of CBC results, attention to changes in the leukocyte differential, implementation of Review Criteria and patient referral for specialist consultation constitute the fundamental principles of differential diagnosis of leukocyte changes.
