Diagnostic accuracy of pleural fluid complement C1q for tuberculous pleural effusion in elderly patients.

BACKGROUND

Previous studies indicated that pleural fluid complement C1q was helpful for diagnosing tuberculous pleural effusion (TPE), but the participants in these studies were young. The diagnostic accuracy of C1q for TPE in elderly patients remains unknown. This study aimed to investigate the diagnostic accuracy of C1q for TPE in elderly patients.

METHODS

We prospectively recruited patients with undiagnosed pleural effusion who visited the Affiliated Hospital of Inner Mongolia Medical University between September 2018 and July 2021. Their C1q in pleural fluid was detected, and the diagnostic accuracy of C1q was assessed by the receiver operating characteristic (ROC) curve analysis.

RESULTS

The median ages of patients with TPE and non-TPE were 75 and 71 years, respectively. TPE patients had significantly higher C1q than non-TPE. The area under the ROC curve (AUC) of C1q was 0.67 (95 %CI: 0.51-0.82). At the threshold of 100 mg/L, C1q had a sensitivity of 0.44 (95 %CI: 0.19-0.69) and specificity of 0.79 (95 %CI: 0.71-0.86).

CONCLUSION

C1q in pleural fluid has low diagnostic accuracy for TPE in elderly patients.