Saudi Thoracic Society pleural effusion integrated local algorithms and recommendations (PILLAR) guideline: evaluation of unilateral pleural effusion

This is the authors' abstract. We don't add key points for this paper.

Unilateral pleural effusion presents diagnostic uncertainty, and Saudi Arabia lacks a nationally endorsed framework for its evaluation. The Saudi Thoracic Society PILLAR guideline provides evidence-based, regionally adapted recommendations for adults in Saudi Arabia and the wider Middle East and North Africa region. A multidisciplinary panel formulated Population, Index test, Comparator, Outcomes questions, searched PubMed and Embase, and assessed evidence using GRADE and the evidence-to-decision framework. Recommendations required at least 75% agreement by anonymous vote. The guideline addresses biochemical classification, thoracic imaging, ultrasound-guided procedures, pleural infection prognosis and microbiology, malignant pleural effusion biomarkers, and tissue acquisition. Light’s criteria remain the biochemical standard, whereas thoracic ultrasound and computed tomography provide complementary assessment. Ultrasound guidance is recommended for pleural procedures. Pleural infection assessment should integrate RAPID scoring, pleural-fluid biochemistry, and microbiology. Cytology remains the initial investigation for suspected malignant effusion, with thoracoscopy or image-guided biopsy selected according to pleural morphology, patient factors, expertise, and resources.