Can this result diagnose a condition on its own?

No. A laboratory result should be interpreted with related tests, symptoms, medical history, and the reference information on the report.

Which reference range should I use?

Use the reference interval provided by the laboratory that performed the test. Clinical decision cutoffs, when relevant, are shown separately.

When should I discuss the result with a healthcare professional?

Professional assessment is appropriate when a result is markedly outside the reference interval, serious symptoms are present, an abnormality persists or recurs, or follow-up has been recommended.

Information about a laboratory test

High Lymphocytes: What Does It Mean?

A high lymphocyte count can occur with some viral infections and certain hematologic conditions.

Test summary

Test name: Lymphocytes
Abbreviations: LYM, Lymph
Category: Hematology / Immunology
Panel: WBC Differential / Hemogram
Specimen: Whole blood
Common units: %, /µL, x10^9/L

What does the test measure?

Shows the percentage or absolute number of lymphocytes, which include important immune-cell groups such as B cells, T cells, and natural killer cells.

Why is the test ordered?

Used with the total WBC count and other white-cell subtypes when evaluating infections and conditions that affect the immune system.

Information about a low result

A low lymphocyte count can occur with some infections, medicines, immune suppression, or bone-marrow problems.

Information about a high result

A high lymphocyte count can occur with some viral infections and certain hematologic conditions.

Reference and clinical context

Use the reference interval printed on your own laboratory report first. Reference intervals may vary by laboratory, method, unit, age, sex, pregnancy, specimen, and other conditions. Numeric records in this workbook are explicitly labeled as either source-based example reference intervals or clinical decision cutoffs.

Reference range 1

>= 20 – <= 40 %

Population: General
Specimen: Whole blood

Example differential percentage

MedlinePlus example differential percentage; absolute counts and lab-specific ranges may be more relevant.

Reference ranges may vary by laboratory, method used, age, sex, pregnancy status, and clinical context. The reference range on your own laboratory report takes precedence.

Interpretation notes

Lymphocytosis can occur with viral infections, but it is not by itself a diagnosis of a viral infection.

Related specialties

Hematology
Infectious Diseases
Internal Medicine
Pediatrics

Frequently asked questions

Sources

Blood Differential — U.S. National Library of Medicine (MedlinePlus)
Government medical reference · 2024 · Neutrophil, lymphocyte, monocyte, eosinophil, basophil roles and example percentages · Verified: Aug 11, 2026