Optimizing Diagnostic Strategies for Malignant Serous Cavity Effusion: The Role of Cytomorphological Examination Combined with High Fluorescent Cells and Total Protein

Ning Zhang^1,#, Yingfei Duan^2,#, Thomas Stuart Mughogho³, Dokani Michael Ndovi³, Rashid Kaseka³, Jian Hu1, Jie Zheng⁴, Xiaoqin Wang¹,*

1. Department of Clinical Laboratory, The First Affiliated Hospital of Xi’an Jiaotong University, 277# West Yanta Road, Xi’an, 710061, Shaanxi Province, China
2. Department of Pathology, The First Affiliated Hospital of Xi’an Jiaotong University, 277# West Yanta Road, Xi’an, 710061, Shaanxi Province, China
3. Laboratory Department, Mzuzu Central Hospital, Private Bag 209, Luwinga, Mzuzu 2, Malawi
4. Department of Radiology, The First Affiliated Hospital of Xi’an Jiaotong University, 277# West Yanta Road, Xi’an, 710061, Shaanxi Province, China

*Corresponding Author: Jie Zheng; Email:jiezheng@xjtu.edu.cn, Xiaoqin Wang; Email: wxq1493722680@xjtufh.edu.cn, These authors jointly supervised this work

Abstract
Objective
This study evaluated the diagnostic value of cytomorphological examination in malignant serous cavity effusion (MSCE) and optimized clinical strategies by integrating routine cytological and biochemical analysis.
Methods
A retrospective analysis was conducted on 3,998 patients with serous cavity effusion at the First Affiliated Hospital of Xi’an Jiaotong University. Based on cytopathological results, patients were classified into MSCE (1,078 cases) and benign serous cavity effusion (BSCE, 2,920 cases) groups. Diagnostic performance of cytomorphological examination was assessed, and routine cytological and biochemical parameters were compared. Receiver operating characteristic (ROC) curves were used to evaluate diagnostic efficacy.
Results
Cytomorphological examination showed a sensitivity of 82.9%, specificity of 86.3%, and accuracy of 85.0%, with high concordance with cytopathological diagnosis (κ = 0.687, P < 0.001). High fluorescence cell count (HFC) and total protein (TP) were significantly elevated in the MSCE group and positively correlated with MSCE (P < 0.001). HFC (AUC: 0.765, 95% CI: 0.748–0.782; cutoff: 24.5×106/L) and TP (AUC: 0.735, 95% CI: 0.719–0.750; cutoff: 29.75 g/L) combined with cytomorphological examination provided supplementary diagnostic value. Two combinatorial diagnostic strategies based on cytomorphological examination, HFC, and TP were developed, with Strategy I achieving 93.4% sensitivity and 72.6% specificity, and Strategy II achieving 92.3% specificity and 78.9% sensitivity. Both strategies showed substantial concordance with cytopathological diagnosis (κ=0.622/0.724, P < 0.001).
Conclusion
Cytomorphological examination showed high sensitivity and high specificity in the diagnosis of MSCE. Its combination with HFC and TP effectively enhances diagnostic performance by achieving a balance between reducing missed diagnoses and minimizing misdiagnoses.

Key Words: cytomorphological examination; malignant serous cavity effusion; high fluorescent cell; total protein; diagnostic strategy