Automated flow cytometric analysis of cerebrospinal fluid

BACKGROUND: Recently, the UF-100 (Sysmex Corporation) flow cytometer was developed to automate urinalysis. We evaluated the use of flow cytometry in the analysis of cerebrospinal fluid (CSF). METHODS: UF-100 data were correlated with microscopy and biochemical data for 256 CSF samples. Microbiological analysis was performed in 144 suspected cases of meningitis. RESULTS: Good agreement was obtained between UF-100 and microscopy data for erythrocytes (r = 0.919) and leukocytes (r = 0.886). In some cases, however, incorrect classification of lymphocytes by the UF-100 led to underestimation of the leukocyte count. UF-100 bacterial count positively correlated (P < 0.001) with UF-100 leukocyte count (r = 0.666), CSF total protein (r = 0.754), and CSF lactate concentrations (r = 0.641), and negatively correlated with CSF glucose concentration (r = -0.405; P < 0.001). UF-100 bacterial counts were unreliable in hemorrhagic samples and in samples collected by ventricular drainage where interference by blood platelets and cell debris was observed. Another major problem was the UF-100 "bacterial" background signal in sterile CSF samples. Cryptococcus neoformans yeast cells and cholesterol crystals in craniopharyngioma were detected by the flow cytometer. CONCLUSIONS: Flow cytometry of CSF with the UF-100 offers a rapid and reliable leukocytes and erythrocyte count. Additional settings offered by the instrument may be useful in the diagnosis of neurological disorders.