After lavage through the alveoli, the lavage fluid extracted can be examined to clarify the problem. The results include the following: cytology, including the count and classification of nucleated cells, as well as subpopulation analysis of lymphocytes and tumor cells, which can indicate the presence of inflammatory reactions, allergic factors and antigenic antibodies, respectively, including bronchoalveolar carcinoma and small cell lung cancer in the lung. In addition, molecular composition tests, including proteins, enzymes, and immunoglobulins, can clarify the composition of the proteins contained, which can help in the diagnosis of diseases of the immune system. In addition, microbiological tests, including parasites, can clarify the infection, including protozoa, leptospira, and pulmonary schistosomes, which can help to confirm the diagnosis of the disease.