Bronchoalveolar lavage cell differential on microscope glass cover. A simple and accurate technique

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 less than 0.005). Comparison of glass cover and cytocentrifuge preparation mixtures with varying amounts (20 to 80%) of purified blood leukocytes labeled with 51Cr (greater than or equal to 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 neutrophil 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 percentages 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).(ABSTRACT TRUNCATED AT 250 WORDS)