The clinical utility of joined detection of cancer ratio, cancer ratio plus, Interferon gamma (IFN-ϒ) & Carcinoembryonic antigen (CEA) in differentiating lymphocytic pleural effusions

The differentiation between malignant (MPE) and tuberculous (TPE) pleural effusions should be considered in any patient with an exudative lymphocytic pleural effusion. A rapid precise diagnosis is valuable as the treatment and prognosis are totally different. The histopathological proof may shorten the time to differential diagnosis. But it may be invasive and costly. The aim of this study is to validate the clinical reliability of joined detection of cancer ratio (serum LDH to pleural ADA), cancer ratio plus (cancer ratio to percentage of pleural fluid lymphocytic count), pleural interferon gamma (pIFN-ϒ), and pleural carcinoembryonic antigen (pCEA) values to differentiate between lymphocytic pleural effusions. Seventy-eight patients were included with mean age ± SD 53.09 ± 9.56 years old, 49 males and 29 females, diagnosed as 47 MPE, 24 TPE, and 7 others. Cancer ratio at cutoff value of ≥ 22 and cancer ration plus at cutoff value of ≥ 41 can discriminate MPE from any other cause with sensitivity (91.5%, 93.6%), specificity (87.5%, 91.7%), and diagnostic accuracy (90.1%, 92.9%) respectively. When the levels of pCEA and pIFN-ϒ were combined with cutoff value of cancer ratio, there were powerful diagnostic differentiating results. Cancer ratio and cancer ratio plus offered valid, efficient, non-invasive, and easy measuring diagnostic tools. On diagnostic uncertainty, the add-on of pCEA in cases of suspected MPE, and pIFN-ϒ in cases of suspected TPE has a trustable diagnostic efficacy with no need for further investigations.