Lymphocytes
Lymphocytes include T cells (cellular immunity), B cells (antibody production), and natural killer (NK) cells (innate antiviral and antitumor defense). They typically comprise 20–40% of the WBC differential and are the backbone of adaptive immunity.
Elevated lymphocytes (lymphocytosis) most commonly indicate viral infection (EBV, CMV, hepatitis), but can also occur in chronic lymphocytic leukemia and autoimmune conditions. Low lymphocytes (lymphopenia) may result from HIV, corticosteroid therapy, chemotherapy, or severe acute illness.
The absolute lymphocyte count is more clinically meaningful than the percentage, as the percentage can be misleadingly low when neutrophils are elevated (and vice versa).
What It Measures
Absolute count and relative percentage of lymphocytes (T cells, B cells, NK cells) in the white blood cell differential.
Reference Ranges
| Status | Range (K/uL) |
|---|---|
| Optimal | 1.5–3.0 K/uL (absolute) |
| Normal | 1.0–4.8 K/uL (absolute), 20–40% |
| Borderline | 0.8–1.0 K/uL |
| Out of Range | < 0.8 K/uL (lymphopenia) or > 5.0 K/uL |
How GATOR Tracks This
Lab Providers
Related Clinical Ratios
Related Biomarkers
This content is for informational purposes only and does not constitute medical advice. Reference ranges may vary by laboratory and individual factors. Consult a qualified healthcare provider for interpretation of your results and treatment decisions.
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