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

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.

The preservation method and timing on accuracy of manual leukocytes counts in synovial fluid.

OBJECTIVES: To compare the efficacy of heparin and EDTA and determine the impact of time delays in stabilizing leukocyte counts in synovial fluid. MATERIAL AND METHOD: 33 specimens were collected in heparin-preserved and EDTA-preserved containers. Total cell count was performed manually at 1 hour and 24 hours. Correlation between cell counts from both preservatives and the leukocyte number at 1 hour and 24 hours were analyzed by means of agreement measurement. RESULTS: There were good correlations between the leukocyte numbers from the specimens preserved by heparin and EDTA (ICC = 0.889, r = 0.879, P < 0.0001 at 1 hour and ICC = 0.822, r = 0.693, p < 0.0001 at 24 hour). At 24 hours, total cell counts from EDTA-preserved samples were comparable to those obtained at 1 hour (ICC = 0.985, r = 0. 986, p < 0. 0001) and were not different from those of the heparinized samples (ICC = 0.833, r = 0. 751, p < 0.0001) but the ICC value was higher. CONCLUSION: EDTA was as effective as heparin for preservation of synovial fluid. Therefore, it can be used routinely as a preservative of synovial fluid.