Lymphocytosis refers to an increase of peripheral blood lymphocytes, which for adults is defined as an absolute lymphocyte count (ALC) > 5.0 x 109/L. Lymphocytes generally constitute 8-33% of white blood cell count (WBC) in peripheral blood. The normal number and distribution of lymphocyte subsets vary with age.

Edupath Newsletter May 2020 – Lymphocytosis