The diagnostic ability of high-fluorescent cells combined with carcinoembryonic antigen for malignant pleural effusion

Introduction: High-fluorescent cells (HFCs) that are detected with an automated hematology analyzer may be useful for the detection of tumor cells; however, the diagnostic ability of HFCs for differentiating malignant pleural effusion is limited. The aim of this study was to investigate the diagnostic value of the combined detection of HFCs with the tumor marker carcinoembryonic antigen (CEA) for the identification of malignant hydrothorax. Methods: A total of 115 pleural effusions were collected. HFCs, including the relative counts (HF-BF%) and absolute counts (HF-BF#), were analyzed using the BF mode of a Sysmex XN9000 hematology analyzer. Simultaneously, the CEA level from the same patient was measured by an electrochemiluminescence method. Receiver operating characteristic (ROC) curve analysis was employed to evaluate the diagnostic accuracy of HFCs separately or combined with CEA analysis for malignant diseases. Results: The levels of HF-BF#, HF-BF%, and CEA in the malignant effusion group were significantly higher than those in the benign control group. The diagnostic value of the HF-BF# and HF-BF% for malignant pleural effusion was low to moderate, and the area under the curve (AUC) was 0.663 and 0.715, respectively. The CEA detection showed a moderate diagnostic ability, and the AUC was 0.832. The AUC for the combined methods was 0.860 and 0.890, respectively. The cutoff levels of the HF-BF#, HF-BF%, and CEA levels were 29.5 × 10⁶/L, 5.6/100 WBC, and 4.795 ng/mL, respectively. Conclusions: The combined detection of high-fluorescent cells with the BF mode and CEA testing may be a good indication for malignancy.