leukocytdifferensieringsmarkør

Leukocyte differential, or differential white blood cell count, is a laboratory test that quantifies the relative proportions and absolute numbers of the major white blood cell types in peripheral blood. It is usually reported as percentages of total leukocytes and, when combined with a complete blood count (CBC) with differential (CBC-D), an absolute count per microliter is provided for each cell type. The standard categories are neutrophils, lymphocytes, monocytes, eosinophils, and basophils; in many laboratories, immature granulocytes (such as bands, metamyelocytes) may also be reported, and automated systems may be supplemented by manual review of a stained smear.

Results are used to diagnose and monitor infections, inflammatory conditions, allergic diseases, and hematologic disorders. A shift in the differential can indicate different processes: neutrophilia often reflects bacterial infection or inflammation; neutropenia can predispose to infection; lymphocytosis can be seen in viral infections or certain diseases; lymphopenia in stress, steroids, or immune suppression; eosinophilia suggests allergic disorders, parasitic infection, or certain drug reactions; basophilia is uncommon but can occur in hypersensitivity or myeloproliferative disorders. Abnormal increases in immature granulocytes may point to marrow stimulation or leukemia.

Reference ranges vary by age and laboratory, but often neutrophils are about 40–60%, lymphocytes 20–40%, monocytes 2–8%, eosinophils 1–4%, and basophils 0–1%. Results are interpreted in the clinical context and may be influenced by sampling conditions, pregnancy, medications, or stress.