Enzyme activities, protein content and cellular variables in the pulmonary epithelial lining fluid in selected healthy pigs.

Reference values of cellular and non-cellular components in the bronchoalveolar lavage fluid (BALF) were established from the BALF specimens obtained from 52 healthy pigs. Using urea as an endogenous marker of dilution, the reference values in the epithelial lining fluid (ELF) were calculated: total cell count 2.71 x 10(9) - 56.49 x 10(9) litre(-1) ELF, alveolar macrophages 2.02 x 10(9) - 49.91 x 10(9) litre(-1) ELF, lymphocytes 0.10 x 10(9) - 4.74 x 10(9) litre(-1) ELF, polymorphonuclear neutrophils 0.01 x 10(9) - 3.48 x 10(9) litre(-1) ELF, protein 0.10 - 13.13 g litre(-1) ELF, lactate dehydrogenase 127-1843 Units litre(-1) ELF, and alkaline phosphatase 86-994 Units litre(-1) ELF. The problems of quantification of BALF components are discussed and a standardized lavage protocol in swine is described, which is essential for the interpretation of diagnostic findings and for the comparison of different BALF specimens.