Flow Cytometric Analysis of Cerebrospinal Fluid Has Low Diagnostic Yield in Samples Without Atypical Morphology or Prior History of Hematologic Malignancy

Objectives: To identify pretest characteristics of cerebrospinal fluid (CSF) specimens that will allow the rational use of flow cytometric analysis (FCA) in the diagnosis of hematologic malignancy. Methods: Retrospective data were collected on 501 consecutive CSF samples submitted for FCA. Results: A positive diagnosis of hematologic malignancy was made in 41 specimens (8.2%). Blasts or atypical lymphocytes were noted on Wright-stained slides in 98% of FCA-positive specimens (40/41), and a history of a hematologic malignancy was present in 89% of specimens (34/38). All FCA-positive specimens had atypical morphology or history of hematologic malignancy. Four hundred six specimens (81%) were FCA negative. Of FCA-negative specimens, 7% (30/406) had atypical morphology, and 3% (12/404) had future central nervous system involvement seen within 30 days.