see also:

• full blood examination (FBE)
• lymphocytosis
• neutropenia

• most commonly is due to viral infections but also occurs with many states which cause either:
  • neutrophilia
    • such as acute stress response (including exercise), corticosteroids, inflammation including bacterial infections, rheumatoid arthritis, systemic lupus erythematosus (SLE), etc.
  • neutropenia
    • impaired bone marrow functional capacity such as radiation injury, cytotoxic agents, leukaemia, lymphoma, aplastic anaemia
• a low T cell count may indicate HIV / AIDS