What does an absolute lymphocyte count (ALC) of 1718 cells per microliter (cells/μL) mean?

Absolute Lymphocyte Count of 1718 cells/μL is Within Normal Range

An absolute lymphocyte count (ALC) of 1718 cells/μL is within the normal reference range for adults and does not indicate any specific disease process. 1

Understanding Absolute Lymphocyte Count

• Normal absolute lymphocyte counts typically range between 1000-4800 cells/μL in adults, with some variation depending on the laboratory reference ranges 1
• The value of 1718 cells/μL falls well within this normal range and does not suggest lymphocytopenia (low lymphocyte count) or lymphocytosis (elevated lymphocyte count) 2
• This normal count suggests adequate immune function, as lymphocytes are important components of the immune system 3

Clinical Significance

• A normal ALC indicates that this particular aspect of the immune system is functioning appropriately 4
• This value alone does not suggest any hematologic malignancy such as chronic lymphocytic leukemia (CLL), which typically presents with an ALC greater than 5000 cells/μL 1
• For CLL diagnosis, an absolute lymphocyte count must exceed 5000 cells/μL (5 × 10^9/L) of mature-appearing lymphocytes in the peripheral blood, along with specific immunophenotypic features 1

When to Consider Further Evaluation

• An isolated normal ALC of 1718 cells/μL generally does not require additional investigation in the absence of other concerning symptoms or abnormal laboratory findings 5
• If clinical suspicion exists for an underlying condition despite normal ALC, additional testing might include:
  • Complete blood count with differential to evaluate other cell lines 1
  • Flow cytometry if a lymphoproliferative disorder is suspected despite normal counts 1
  • Evaluation for potential causes of relative lymphocytosis if the percentage of lymphocytes is elevated despite normal absolute count 5

Monitoring Considerations

• A single normal ALC value provides a snapshot of current immune status but may not reflect dynamic changes 2
• Serial measurements may be more informative if monitoring for disease progression or treatment response in certain conditions 1
• The ALC should always be interpreted in the context of the patient's clinical presentation, other laboratory values, and medical history 4

Common Pitfalls in Interpretation

• Avoid over-interpreting an isolated normal laboratory value without clinical context 1
• Remember that transient fluctuations in lymphocyte counts can occur with stress, exercise, or time of day 2
• Do not use ALC as the sole criterion for diagnosing or excluding conditions like CLL, which require additional specific diagnostic criteria 1