It is because lymphoma has no specific clinical manifestations that the diagnosis of lymphoma is more complicated than other diseases. The gold standard for diagnosis of malignant tumors is pathological examination of tissues and organs, and so is lymphoma, whose gold standard for diagnosis is pathological examination of lymphatic tissue biopsy, of which lymph nodes are the most commonly invaded lymphatic tissues, so lymph node biopsy is the most commonly used diagnostic tool. Since all tissue biopsies are invasive, especially lymph node biopsies of the thoracic and abdominal cavities and splenectomies, if lymphoma is suspected, further screening should be performed at the hospital to first exclude the corresponding clinical manifestations caused by other diseases, such as swollen lymph nodes due to infection. What tests should be performed for lymphoma? Since lymphoma often spreads systemically, CT examinations of the neck, chest and abdomen should be performed at the early stage of the disease to evaluate the enlargement of lymph nodes throughout the body and to stage the disease, which plays a key role in guiding the treatment of lymphoma. Bone marrow aspiration biopsy is very critical. Routine bone marrow aspiration biopsy can detect bone marrow invasion at an early stage, and those with bone marrow invasion often indicate poor prognosis and need stronger treatment. Bone marrow aspiration biopsy is often neglected by many units, especially oncology hospitals, because it is an operation performed by the hematology department, and many oncology hospitals do not have a hematology department and do not perform it routinely. Liver and kidney function, lactate dehydrogenase and other tests should be routinely performed. Currently, it is believed that lymphoma occurs in a certain genetic background, that is, the chromosomes or genes of lymphoma cells are different from normal cells. Moreover, these chromosomal or genetic alterations may be the real cause of lymphoma, and patients carrying different chromosomal or genetic alterations have different treatment and prognosis. Therefore, genetic tests should also be performed for each patient. Due to the limitation of domestic conditions, few units can perform such tests, and only the Hospital of Blood Diseases of the Chinese Academy of Medical Sciences (Institute of Blood Research) in Tianjin can perform such tests.