What does a low lymphocyte percentage indicate?

Lymphocytes are a type of white blood cell (WBC) in the human body, accounting for approximately 20%–40% of all WBCs. A lymphocyte percentage below 20% is considered decreased. So, what causes a low lymphocyte percentage? Below is an explanation.

What Causes a Low Lymphocyte Percentage?

1. Inflammatory Infection

A decreased lymphocyte percentage may result from an inflammatory or infectious process in the body. A relatively low lymphocyte percentage often corresponds to a relatively elevated neutrophil percentage. Further diagnostic testing is required to identify the specific site of inflammation.

2. Drug-Related Factors

In addition to the above causes, certain medications may also lead to reduced lymphocyte percentages. Clinically, drugs such as corticosteroids, alkylating agents, and anti-lymphocyte globulin may lower lymphocyte counts during treatment. In such cases, discontinuation of the offending drug typically leads to normalization of the lymphocyte percentage.

3. Immunosuppression

When a patient’s immune function declines, lymphocyte percentage may also decrease. If the reduction is only mild and remains close to the lower limit of normal, no specific treatment is usually required. However, patients should maintain regular physical exercise and undergo periodic blood tests.

4. Radiation Injury

A low lymphocyte percentage is commonly observed in individuals exposed to ionizing radiation, those with immunodeficiency disorders, or patients with hypogammaglobulinemia. If significantly low lymphocyte counts are detected during routine examination, comprehensive preventive measures should be implemented promptly, along with thorough diagnostic evaluation and targeted treatment for the underlying condition—thereby effectively managing each patient’s disease course.

The above outlines the potential causes of a low lymphocyte percentage. We hope this information is helpful to you.