The routine blood test can detect lymphatic system diseases, because the routine blood test includes neutrophils and lymphocytes, eosinophils, so if there is a lymphatic system disease, the lymphocyte count and percentage can be increased. However, routine blood tests can only be used as a preliminary screening for lymphatic system diseases, which generally include localized lymphadenitis and do not make much difference in clinical treatment. What needs to be highly vigilant is malignant diseases of the lymphatic system, including lymphoma or lymphoblastic leukemia, for lymphoma or lymphoblastic leukemia, the lymphocyte count is usually significantly elevated or exceeds the normal range by a great deal. For routine blood tests, if the lymphocyte count or percentage exceeds the normal value, it is usually necessary to do further lymph node biopsy or even bone puncture examination to exclude the possibility of malignant tumors in the lymphatic system. So routine blood tests can check for diseases of the lymphatic system, but if malignant tumors of the lymphatic system are suspected, further lymph node biopsy or even bone puncture tests are usually needed to rule out the possibility of lymphoma or even lymphoblastic leukemia.