1. Clinical manifestations: (1) There may be fatigue, decreased physical strength, wasting, hypothermia, anemia or bleeding manifestations. (2) There may be lymph nodes (including head and neck, axilla, groin), liver and spleen enlargement. (2) Laboratory tests: (1) peripheral blood WBC>10×109/L, lymphocyte ratio ≥ 50%, absolute value ≥ 5×109/L, morphology is mainly mature lymphocytes, visible naïve lymphocytes or atypical lymphocytes. (2) Bone marrow picture: active or apparently active bone marrow proliferation, lymphocytes ≥ 40%, mainly mature lymphocytes. (3) Immunophenotyping: (1) B-CLL: positive mouse rose node test: weakly positive for SIg, K or λ monoclonal light chain type; positive for CD5, CD19, CD20; negative for CD10, CD22. (2) T-CLL: positive sheep rose node test: positive for CD2, CD3, CD8 (or CD4), negative for CD5. 4. Morphological typing: B-CLL is divided into 3 subtypes: (1) Typical CLL: more than 90% are similar to mature small lymphocytes. (2) CLL with juvenile lymphocytosis: naïve lymphocytes >10%, but <50%. (3) Mixed cell type: with different proportions of atypical lymphocytes, large cell volume, reduced nuclear/pulp ratio, cytoplasm with different degrees of basophilic staining, with or without asplenophilic granules. T-CLL cell morphology is divided into the following 4 types: (1) Large lymphocyte type: large cell volume, light blue cytoplasm, with fine or coarse asplenophilic granules, round or ovoid nuclei, often to one side, chromatin aggregates into clumps, and rare nucleoli. (2) Naive T-cell type: the nucleus is basophilic, without granules, and the nucleoli are obvious. (3) Small or large lymphocytes with cerebral gyrus-like nuclei. (4) The cell morphology is diverse, and the nuclei are mostly lobulated.