Comparison of conventional manual methods with the ADVIA 120 automated method for counting of red and white blood cells in cerebrospinal fluid.

ABSTRACT

Objective: To evaluate the correlation and agreement of erythrocyte and leukocytes count in cerebrospinal fluid (CSF) among two different manual methods and automated method. Methods: We evaluated the correlations and agreements of the CSF RBC counts, WBC counts and WBC differential counts between two manual methods and automated method by using the ADVIA 120 CSF assay. Results: We studied 83 CSF specimens in all methods. Absolute cell counts showed a high correlation and agreement between methods, with correlation coefficient (rs) for all absolute counts of more than 0.89 and intraclass correlation (ICC) more than 0.9. The correlation and agreement of WBC differential counts from CSF specimens which had more than 20 WBCs/µL were also evaluated, which revealed good results only for polymorphonuclear cells, neutrophils and lymphocytes (rs = 0.796, 0.835 and 0.779, respectively and ICC = 0.954, 0.899 and 0.907, respectively). When WBC counts more than 5 cells/µL in automated method were used as a cut-off point, the sensitivity is 100% but specificity is very low (60.87%). The cut-off point of 5 WBCs/µL for manual method and 11 WBCs/µL for automated method gave the highest agreement (Kappa 0.874, sensitivity 91.43% and specificity 95.65%). Conclusion: The ADVIA 120 CSF assay provide a useful and efficient method for excluding the normal CSF specimens at cut-off 5 WBCs/µL.