Abnormal lymphocyte count can have various causes, ranging in severity from 'minor' to 'generally fatal'. Finding the true cause means ruling out or confirming each possibility – in other words, diagnosis.
Diagnosis is usually a complex process due to the sheer number of possible causes and related symptoms. In order to diagnose abnormal lymphocyte count, we could:
|Whooping Cough||2%||Ruled out|
|Infectious Mononucleosis||0%||Ruled out|
|Guillain-Barre Syndrome||0%||Ruled out|
|Herpes Simplex Type I||0%||Ruled out|
White Blood Cells - Lymphocyte Percentage [fraction]
Possible responses:→ Don't know
→ Under 20% [0.20] (low)
→ 20 to 45% [0.20-0.45] (normal)
→ 46 to 55% [0.46-0.55] (elevated)
→ Over 55% [0.55] (high)
Certain drugs, such as mephenytoin, dilantin and para-aminosalicylic acid, can cause an increased lymphocyte count.
Lymphocytes are made in the bone marrow, so when the bone marrow isn't functioning properly, lymphocyte counts can drop.
Autoimmune problems such as rheumatoid arthritis can cause reduced lymphocyte counts.
A complete blood count may show large numbers of lymphocytes in a pertussis patient.