Summary
Introduction. Complete blood count (CBC) is an essential diagnostic tool for every primary care physician. Lymphocytes, further classified into T and B lymphocytes and NK cells, are important cells of the immune system responsible for humoral and cellular immunity and relevant to the pathogenesis and course of many diseases. Frequently encountered changes in lymphocyte count, detected through CBC, can help suspect an illness, assess the course of the disease, and differentiate a specific condition from others. Precise and informed interpretation of lymphocyte count changes can facilitate the diagnosis of various diseases. Knowledge of the etiological causes of lymphocytosis and lymphocytopenia and adherence to diagnostic algorithms can lead to a smoother diagnostic and treatment process.
Objective of the Study. Perform a literature analysis and present the main causes of changes in lymphocyte count, as well as develop diagnostic algorithms to aid in differentiating various diseases causing lymphocytosis or lymphocytopenia.
Methods. A literature review was conducted using several databases, including PubMed, ScienceDirect, ResearchGate, and other reliable sources, employing free-text search with relevant keywords. Fifty-one studies were selected to fulfill the research objectives, without limitations based on time or a predetermined selection protocol.
Conclusions. Based on the literature analysis conducted, the developed diagnostic algorithms when encountering lymphocytosis or lymphocytopenia in complete blood count, can assist primary care physicians in appropriately responding to each condition that alters the lymphocyte count in peripheral blood. It is important to consider the patient’s medical history and clinical examination findings when deciding to refer the patient for further tests or specialist consultations. Diagnostic algorithms encourage the selection of effective and cost-efficient methods for diagnosing the disease, evaluating disease dynamics, and planning treatment, thus reducing the harm of unnecessary tests and at the same time expediting patient diagnosis.
