The authors applied the mathematical method of discrimination analysis in the differential diagnosis of tumourous and other pleural exudates, as well as for the differentiation of malignant and paramalignant exudates. The basis for the investigation were data obtained during a four-year prospective study of pleural exudates at the Second Clinic of Tuberculosis and Respiratory Diseases in Prague. The analysis was made using a programme elaborated by RNDr. Tomásek, CSc. on a Hewlett-Packard 2100S computer in IHE Prague. After processing of 38 parameters--from 138 patients (without data on the cytology of the exudate, biopsy of the parietal pleura, bronchoscopy and thoracoscopy) the computer selected nine parameters with the greatest discrimination value which made it possible to differentiate tumorous exudates from others in 84%. This concerned the following data: skiagram of chest on admission, CEA in the exudate, temperature, exudate known already before admission to Clinic, LDH in serum on logarithmic scale, general impression of disease during physical examination, red cell sedimentation rate on admission, volume of exudate, alkaline phosphatase in exudate. When it was possible to add to the analyzed parameters also examination of the tissue polypeptide antigen (TPA), the analysis could be performed in 61 subjects. In that case the discriminating capacity rose to 95%. Subsequently we entered in the programme 38 parameters from 88 patients with a tumourous exudate and sought the most suitable ones for differentiation of malignant and paramalignant exudates.(ABSTRACT TRUNCATED AT 250 WORDS)

2 klinika tuberkulózy a respiracních nemocí 1 lékarské fakulty Univerzity Karlovy a fakultní nemocnice 1 Praha