Bronchoalveolar Lavage Cell Differential on Microscope Glass Cover: A Simple and Accurate Technique

Publisher Website
Google Scholar
Abstract
We describe a quick and easy technique to perform cell differentials on bronchoalveolar lavage: the microscope glass cover. Lavage fluids of 72 subjects were analyzed by 3 techniques: glass cover, filter, and cytocentrifuge preparations. Seventy-seven other lavages were analyzed by glass cover and cytocentrifuge preparations alone. Data for the 72 subjects studied by all 3 techniques showed that the cell counts on glass cover and filter preparations were similar, e.g., lymphocytes, 19.2 (range, 0.5 to 94%) and 20.9% (range, 3 to 95%), respectively (Spearman''s correlation coefficient, 0.98). However, on cytocentrifuge preparations, lymphocyte counts were lower (8.3%; range, zero to 87%) and macrophage counts were higher (p < 0.005). Comparison of glass cover and cytocentrifuge preparation mixtures with varying amounts (20 to 80%) of purified blood leukocytes labeled with 51Cr (.gtoreq. 72% lymphocytes) showed that a significant amount of radioactive cells was lost during the cytocentrifuge technique in contrast to the glass cover technique. Because neutrophils represented a low proportion of lavage cells, we also evaluated cell suspensions with known neutrophils contents (10 to 70%); we found no difference in neutrophil counts obtained with the 3 techniques. Lavage data analysis of 40 young nonsmoking volunteers showed that glass cover lymphocyte count was also higher than counts on cytocentrifuge preparations: 16.5% (range, 3 to 45%) and 8.2% (range, 2.5 to 35%), respectively. In this group, the distribution of glass cover lymphocyte percentage was normal (p = 0.21, .chi.2 test), and the one-tailed 95% confidence interval was 18.6 to 34.7% (mean plus 1.65 standard deviation). This study shows that the glass cover preparation, besides giving an accurate cell count, is technically advantageous and preserves cell structure. Therefore, the glass cover, is technique should be considered as a valuable alternative to the filter and cytocentrifuge techniques for the determination of lavage cell differentials.