Low cost-effectiveness of CD3/CD20 immunostains for initial triage of lymphoid-rich effusions: an evidence-based review of the utility of these stains in selecting cases for full hematopathologic workup.
CD3/CD20 immunostains are often performed in the initial cytological evaluation of lymphoid-rich pleural effusions (LR-PE). Most benign LR-PE are predominantly composed of T(CD3+) cells while most malignant LR-PE are of B(CD20+) cell lineage. As part of the effort to contain laboratory costs and improve diagnostic accuracy, there is increasing interest in applying principles of evidence-based pathology to the use of immunostains. In this retrospective study, we reviewed the effectiveness of CD3/CD20 immunostains as a diagnostic or triage tool during the initial evaluation of 258 consecutive LR-PE. 196 (76%) of the LR-PE were ultimately diagnosed as reactive lymphocytosis and 62 (24%) as lymphoma/leukemia (L/L). There was a previous diagnosis of L/L, concurrent diagnostic tissue, and/or clinical evidence of L/L in 44 (71%) of the L/L effusions. An initial diagnosis of L/L was made in the remaining 18 (29%) cases. Sixteen of these 18 cases showed large cells with high-grade features that mandated L/L workup. In only 2 (0.8%) of the 258 LR-PE, CD3/CD20 stains were helpful to identify small cell lymphocytic lymphoma (SLL) in patients without concurrent peripheral lymphocytosis. CD3/CD20 immunostains do not appear to provide a cost-effective method to diagnose or triage the vast majority of LR-PE submitted to a clinical cytology laboratory. An algorithm that considers history, blood counts, and cytomorphology allows for cost-effective selection of LR-PE that warrant comprehensive hematopathologic workup. Our findings underscore the feasibility of applying evidence-based principles to develop guidelines for the cost-effective utilization of immunostains in cytology.
Department of Pathology and Laboratory Medicine, Cedars-Sinai Medical Center, Los Angeles, California 90048, USA. walts@cshs.org
Ann E
AE
Walts
Alberto M
AM
Marchevsky
D000465:Algorithms; D018951:Antigens, CD20 / Q000032:analysis; D017252:CD3 Complex / Q000032:analysis*; D004396:Coloring Agents / Q000737:chemistry; D003362:Cost-Benefit Analysis; D019317:Evidence-Based Medicine; D006402:Hematologic Diseases / Q000175:diagnosis / Q000473:pathology*; D006801:Humans; D007159:Immunologic Tests / Q000379:methods; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000175:diagnosis* / Q000473:pathology; D018655:Lymphocyte Count; D008214:Lymphocytes / Q000473:pathology*; D008218:Lymphocytosis / Q000175:diagnosis / Q000473:pathology; D016066:Pleural Effusion, Malignant / Q000175:diagnosis / Q000473:pathology; D012189:Retrospective Studies
D018951:Antigens, CD20; D017252:CD3 Complex; D004396:Coloring Agents