High percentage of abnormal lymphocytes is common in two conditions, as follows: 1, viral infections: especially EBV infections can lead to the appearance of heterogeneous lymphocytes in peripheral blood, and if the ratio exceeds 10%, it can be diagnosed as infectious mononucleosis, an infectious disease caused by viral infections, and patients often have high fever, enlarged lymph nodes, and abnormal liver function. After standardized antiviral treatment, the abnormal indicators will return to normal. 2. Acute lymphoblastic leukemia: A large number of primitive as well as naive and abnormal lymphocytes can be seen in the peripheral blood of patients with acute lymphoblastic leukemia, and a bone marrow aspiration is required to confirm the diagnosis.