Challenges in pleural tuberculosis diagnosis: existing reference standards and nucleic acid tests

Area of Science:

• Pulmonology
• Infectious Diseases
• Microbiology

Background:

• Pleural tuberculosis (pTB) is a severe manifestation of extrapulmonary tuberculosis.
• Current microbiological diagnostic tests for pTB often lack sufficient accuracy.
• The absence of a standardized composite reference standard complicates pTB diagnosis.

Purpose of the Study:

• To review classification criteria for pTB.
• To assess challenges in pleural fluid-based DNA diagnostic tests.
• To evaluate the diagnostic utility of PCR and Xpert MTB/RIF for pTB.

Main Methods:

• Systematic review of 58 studies analyzing PCR (n=33) and Xpert MTB/RIF (n=25) for pTB diagnosis.
• Analysis of diagnostic accuracy, sensitivity, and specificity of included molecular tests.
• Assessment of heterogeneity in reference standards across studies.

Main Results:

• Heterogeneous reference standards were identified across studies.
• Pooled sensitivity for PCR and Xpert MTB/RIF showed wide ranges (0-100%) and were generally inadequate.
• Xpert MTB/RIF demonstrated consistent high specificity (90-100%), suggesting its utility as a 'rule-in' diagnostic test.

Conclusions:

• Existing molecular tests for pTB diagnosis have limitations in sensitivity.
• Xpert MTB/RIF's high specificity is valuable for confirming pTB cases.
• Well-designed studies are urgently needed to evaluate current and novel molecular tests for accurate pTB diagnosis.