Lymphocytosis

DGRefHelp - NHS Dumfries & Galloway
NHS Dumfries and Galloway

Defined as persistent lymphocyte count of >4.0X109/L.

Transient lymphocytosis is a common finding in blood count in cases of acute viral infection particularly in infectious mononucleosis and pertussis infection,

Active smoking is a well recognised cause of mild lymphocytosis particularly in females

Assessment

  • Careful history (smoking, constitutional symptoms, infection) and examination for adenopathy and / or organomegaly
  • Glandular fever screen when indicated
  • Repeat FBC, film examination in 4-6 weeks
  • Consider cell marker (immunophenotyping) in cases with persistent lymphocyte count > 5.0X109/L

Primary care management

Some cases with CLL show an indolent course and may not require treatment for several years. Such cases will be carefully considered for discharge to primary care for annual monitoring.

Who to refer

Urgent referral

  • Lymphocytosis in association with cytopenia, anaemia, neutropenia, thrombocytopenia
  • Presence of constitutional symptoms (drenching night sweating, significant weight loss, unexplained fever)
  • Splenomegaly, bulky adenopathy
  • Lymphocyte count >20X109/L
  • Cell marker study confirms Clonal B-Lymphocytosis not consistent with CLL

 

Routine referral or advice request

  • Persistent lymphocytosis not meeting the criteria for urgent referral.

Who not to refer

  • Asymptomatic individuals with lymphocyte count <5X109/L

Editorial Information

Last reviewed: 01/10/2024

Next review date: 01/10/2026

Author(s): Muayed Lasebai, Ranjit Thomas, Paul Ames.

Version: 1.0