CRP and neoplasm: In the patients in group B (with at least positive one of the following: ADA, CRP and % of polymorphonuclear cells) included all false positives due to benign release of TM in fluid in both groups, we also found a decrease in sensitivity because this group included fewer malignant effusions and because more than 40% of tumours were non-epithelial, compared with a rate of 18% in group A.