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Serologic findings significantly contribute to the diagnosis of pleuropulmonary amebiasis. Indirect hemagglutination, because of its better sensitivity and easier performance, is the recommended test. Complement fixation and gel diffusion also are sensitive tests. Although, all these tests are nearly always positive in patients with an amebic liver abscess, they are also positive in 60 percent of asymptomatic subjects who pass cysts. Thus, a positive amebic serology test alone would not prove liver involvement. The differential diagnosis of pleuropulmonary amebiasis includes tuberculosis, empyema, cancer and pyogenic lung abscess. Chronic cough, hemoptysis and fever can occur in all of these conditions. The diagnostic process further is confounded by the similar geographic distribution of amebiasis and tuberculosis. The patients with pleuropulmonary amebiasis often are younger than lung cancer patients. Nearly all patients with pleuropulmonary amebiasis have liver involvement. The abscess, usually in the upper aspect of the liver, can cause a reactive pleural change manifested by an exudative pleural effusion. It occurs in 9 to 34 percent of patients with pleuropulmonary involvement. The liver abscess also can rupture through the diaphragm and create an empyema, lung abscess, hepatobronchial fistula or any combination of these. Diaphragmatic rupture is common when pleuropulmonary disease is present. Sixteen of 20 patients with pleuropulmonary disease studied by ultrasound testing had diaphragmatic rupture. Incidences of diaphragmatic disruption may vary from 21 to 96 percent.2-- Rupture is associated with a mortality varying from 5 to 36 percent.