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A pleural exudate that remains undiagnosed after a combined clinical assessment, thoracentesis, and imaging requires a pleural biopsy for a definitive diagnosis. Thoracoscopy is often the first method of choice to obtain tissue as it offers greater sensitivity and there is a perception of less risk. However, with imaging guidance, closed pleural biopsy is a safe, affordable, and effective alternative to diagnose all forms of pleural disease. Ultrasound (US) has several benefits when compared with computed tomography for image-guided biopsy, as it is widely available, can be performed bedside, and does not expose the patient to radiation. If performed in optimal conditions, a transthoracic USguided closed pleural biopsy can yield results comparable to those of thoracoscopy and a marked reduction in the complication rate versus blind biopsy. Abrams and Tru-Cut needles are the most widely used for a closed pleural biopsy. Either may be used with real-time image guidance or with a free-hand image-assisted technique to harvest up to 6 separate tissue samples. The needle choice will depend on the morphology of the lesion observed on imaging. The Tru-Cut is generally preferred for mass lesions of the pleura or pleura that is >20 mm in thickness, and the Abrams for pleural thickening of <20 mm or radiologically normal pleura. A transthoracic US may be used to detect, rule out, and prevent complications, such as bleeding, solid organ injury, or pneumothorax. The ability to perform thoracic US is a necessary skill in current respiratory practice, and US-guided closed pleural biopsy has a critical role in diagnosis. [ABSTRACT FROM AUTHOR]

In high-burden settings, the diagnosis of pleural tuberculosis (TB) is frequently inferred in patients who present with lymphocyte predominant exudative effusions and high adenosine deaminase (ADA) levels. Two recent small retrospective studies suggested that the lactate dehydrogenase (LDH)/ADA ratio is significantly lower in TB than in non-TB pleural effusions and that the LDH/ADA ratio may be useful in differentiating pleural TB from other pleural exudates. We compared the pleural LDH/ADA ratios, ADA levels, and lymphocyte predominance of a prospectively collected cohort of patients with proven pleural TB (n = 160) to those with a definitive alternative diagnosis (n = 68). The mean pleural fluid LDH/ADA ratio was lower in patients with pleural TB than alternative diagnoses (6.2 vs. 34.3, p < 0.001). The area under the receiver operating characteristic curve was 0.92 (p < 0.001) for LDH/ADA ratio and 0.88 (p < 0.001) for an ADA ≥40 U/L alone. A ratio of ≤12.5 had the best overall diagnostic efficiency, while a ratio of ≤10 had a specificity of 90% and a positive predictive value of 95%, with a sensitivity of 78%, making it a clinically useful "rule in" value for pleural TB in high incidence settings. When comparing the LDH/ADA ratio to an ADA level ≥40 U/L in the presence of a lymphocyte predominant effusion, the latter performed better. When lymphocyte values are unavailable, our data suggest that the LDH/ADA ratio is valuable in distinguishing TB effusions from other pleural exudates. [ABSTRACT FROM AUTHOR]

Bronchoalveolar lavage (BAL) is becoming a common procedure for research into infectious disease immunology. Little is known about the clinical factors which influence the main outcomes of the procedure. In research participants who underwent BAL according to guidelines, the BAL volume yield, and cell yield, concentration, viability, pellet colour and differential count were analysed for association with important participant characteristics such as active tuberculosis (TB) disease, TB exposure, HIV infection and recent SARS-CoV-2 infection. In 337 participants, BAL volume and BAL cell count were correlated in those with active TB disease, and current smokers. The right middle lobe yielded the highest volume. BAL cell and volume yields were lower in older participants, who also had more neutrophils. Current smokers yielded lower volumes and higher numbers of all cell types, and usually had a black pellet. Active TB disease was associated with higher cell yields, and higher proportions of granulocytes, but this declined at the end of treatment. HIV infection was associated with lower cell yields and more bloody pellets, and recent SARS-CoV-2 infection with a higher proportion of lymphocytes. These results allow researchers to optimise their participant and end assay selection for projects involving lung immune cells.