What it is: A lymphocyte count measures the number of lymphocytes — white blood cells including T-cells, B-cells, and natural killer cells — typically as part of a CBC with differential.
Why it's ordered: Ordered alongside a CBC with differential to help evaluate viral infections, immune system function, or suspected blood cancers like leukemia or lymphoma.
What it detects: Lymphocytes fight viral infections and help the immune system "remember" past infections. High counts (lymphocytosis) often reflect viral infection or, less commonly, leukemia/lymphoma; low counts (lymphopenia) can reflect immunosuppression, bone marrow failure, or chemotherapy effects.
Collection & prep: A standard blood draw from a vein in the arm, as part of a CBC with differential. No special preparation is needed.
Results:
High – often linked to viral infection; can also reflect leukemia or lymphoma
Low – can reflect immunosuppression, HIV/AIDS, bone marrow failure, or chemotherapy
Normal – typically 20–40% of total white blood cells
Possible complications: Persistently abnormal lymphocyte counts, especially with other symptoms, may prompt further testing such as a peripheral smear or flow cytometry to rule out a lymphoproliferative disorder.
What it is: A lymphocyte count measures the number of lymphocytes — white blood cells including T-cells, B-cells, and natural killer cells — typically as part of a CBC with differential.
Why it's ordered: Ordered alongside a CBC with differential to help evaluate viral infections, immune system function, or suspected blood cancers like leukemia or lymphoma.
What it detects: Lymphocytes fight viral infections and help the immune system "remember" past infections. High counts (lymphocytosis) often reflect viral infection or, less commonly, leukemia/lymphoma; low counts (lymphopenia) can reflect immunosuppression, bone marrow failure, or chemotherapy effects.
Collection & prep: A standard blood draw from a vein in the arm, as part of a CBC with differential. No special preparation is needed.
Results:
High – often linked to viral infection; can also reflect leukemia or lymphoma
Low – can reflect immunosuppression, HIV/AIDS, bone marrow failure, or chemotherapy
Normal – typically 20–40% of total white blood cells
Possible complications: Persistently abnormal lymphocyte counts, especially with other symptoms, may prompt further testing such as a peripheral smear or flow cytometry to rule out a lymphoproliferative disorder.
Statements made in the Clinical Manual have not been evaluated by the FDA. The products mentioned are not intended to diagnose, treat, cure or prevent any disease.
