Lymphocytes
Disclaimer: Information on this page is for educational purposes. Consult a physician to interpret your test results. Health Vault helps track biomarker trends but does not replace medical advice.
What This Test Measures
Lymphocytes are adaptive immune cells: T cells destroy infected cells, B cells produce antibodies. They are central to viral infections and immune memory.
Lymphocytosis is common in viral infections (EBV, CMV, influenza), chronic lymphocytic leukemia, and hypothyroidism. Lymphopenia occurs in HIV, corticosteroid use, severe infections, and stress.
Absolute lymphocyte count matters more than percentage, especially when total WBC is altered.
Normal Ranges
| Group | Reference Range |
|---|---|
| Men | 20–40% (1.0–4.0 × 10⁹/L) |
| Women | 20–40% (1.0–4.0 × 10⁹/L) |
| Children | 40–60% (higher than adults) |
Reference ranges may vary by laboratory and assay method.
Causes of High Levels
- Viral infections (mononucleosis, CMV)
- Chronic lymphocytic leukemia
- Smoking (relative lymphocytosis)
- Hypothyroidism
Causes of Low Levels
- HIV/AIDS
- Corticosteroids, chemotherapy
- Severe bacterial sepsis
- Autoimmune diseases
- Malnutrition
Test Preparation
- No preparation required
Related Biomarkers
| Biomarker | Relationship |
|---|---|
| White Blood Cells | Total leukocyte count |
| Neutrophils | Ratio in infections |
| Monocytes | Mononuclear phagocytes |
FAQ
How often should I take this test?
With CBC — annually; with HIV and immunodeficiency — regular monitoring.
What should I do if my result is abnormal?
Persistent lymphocytosis warrants CLL evaluation. Lymphopenia requires immune status assessment.
Last updated: June 2026