Pleural homocysteine for malignant pleural effusion: A prospective and double‐blind diagnostic test accuracy study

OBJECTIVE: To assess the accuracy of pleural fluid homocysteine for discriminating malignant pleural effusion (MPE) and benign pleural effusion (BPE). METHODS: A total of 194 patients from two cohorts (Hohhot and Changshu) with undiagnosed pleural effusion were prospectively enrolled. Their pleural homocysteine was measured, and its diagnostic accuracy and net benefit for MPE were analyzed by receiver operating characteristic (ROC) curve analysis and decision curve analysis, respectively. RESULTS: In the Hohhot cohort (n = 136) and the Changshu cohort (n = 58), MPE patients had significantly higher homocysteine levels than BPE patients. The areas under the ROC curves of homocysteine for the diagnosis of MPE were 0.61 (p = 0.027) and 0.59 (p = 0.247), respectively. The decision curves of homocysteine were close to the reference line in both the Hohhot cohort and the Changshu cohort. CONCLUSION: The diagnostic accuracy of pleural fluid homocysteine for MPE was low.