Use of the Advia 120 hematology analyzer in the differential cytologic analysis of biological fluids (cerebrospinal, peritoneal, pleural, pericardial, synovial, and others).

The centralization of our laboratories and the demand for new parameters to measure have led to an increase in the number of biological fluid samples, which are generally sent for urgent analysis. Due to this they cannot be processed by manual methods. Meeting this increased demand for assistance is a challenge for the laboratory, and the challenge has been met by the automated hematology area. A study of the reliability of the Advia 120 hematology analyzer has been carried out through leukocyte and red blood cell counting of 179 biological fluids: cerebrospinal, peritoneal or ascitic, pleural, pericardial, synovial, and others. The automated leukocyte counts of cerebrospinal fluid samples containing up to 0.150 x 10(9) leukocytes/L are correlated with counts obtained with the manual reference method in a Neubauer counting chamber (r = 0.958; P = .0001). Applying Passing-Bablok regression analysis to these results indicates a slope p of 1.155 (95% confidence interval [CI], 0.915-1.347) and an ordinate intercept b of 0.0076 (95% CI, 0.012-0.034), showing the results to be perfectly interchangeable. In the comparison of the manual analysis of the leukocyte differential using the May-Grünwald-Giemsa staining method with the analysis using the automated method, the percentage of polymorphonuclear granulocytes of the Advia 120 basophil/lobularity method is significantly correlated (r = 0.844; P = .0001) with that obtained with the manual count. The results of Passing-Bablok regression analysis (p = 0.859 [95% CI, 0.58-1.190]; b = 8.8 [95% CI, -12.09-24.2]) indicate that these two counting methods are also perfectly interchangeable. Automated leukocyte and differential counts of peritoneal or ascitic fluids also show good correlations with the manual method, and the results are not statistically different. Pretreating synovial fluid samples with hyaluronidase enzyme allows their processing on the Advia 120; no significant differences were found between manual and automated methods with respect to leukocyte counts and differentials. Finally, results with pleural fluid samples indicated that leukocyte and differential counts obtained with the Advia 120 showed significant differences from results obtained with manual methods because of the high incidence of mesothelial, lymphoid, and other tumoral cells in this kind of fluid sample. This result shows that use of hematology analyzers is questionable for these kinds of samples, especially from oncology patients with tumors. A procedure is proposed for the processing of these pleural fluids.