Evaluation of Diagnostic Value of Urinary Deep Stick in Differentiating Different Types of Exudative Pleural Effusions and Differentiating Exudative Pleural Effusions From Transudates

Objective: Rapid diagnosis is one of the key factors in pleural effusion management. Dipstick has been suggested for use in other body fluids, while its role in pleural effusion has not yet been confirmed. This study was conducted with the aim of investigating the diagnostic value of dipstick in differentiating types of pleural effusion. Methods: This prospective study was conducted on 70 patients diagnosed with pleural effusion requiring thoracentesis in Ahvaz teaching hospitals in 2022. Microbiological and cytological laboratory tests were performed on pleural fluid samples. At the same time, pleural fluid samples were evaluated with a urine dipstick. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of dipstick parameters in differentiating types of pleural effusion were calculated in comparison with the standard diagnostic method. Results: The dipstick protein test had a sensitivity of 100%, specificity of 96.23%, PPV of 89.5%, and NPV of 100% for differentiating exudative from transudative effusions, and a sensitivity, specificity, PPV, and NPV of 40%, 100%, 100%, and 61.5%, respectively, in detecting infectious exudative effusions. Sensitivity, specificity, PPV, and NPV of the dipstick leukocyte esterase test in differentiating exudative from transudative effusions were 100%, 56.6%, 42.5%, and 100%, respectively, and in detecting different types of exudative effusions, sensitivity, specificity, PPV, and NPV were all 100%. The dipstick glucose test effectively differentiated exudative from transudative effusions (sensitivity, specificity, PPV, and NPV of 82.35%, 79.25%, 56.0%, and 93.3%, respectively) and detected infectious exudative effusions (sensitivity, 93.33%, specificity, 93.30%, PPV, 93.3%, NPV, 91.3%). Sensitivity, specificity, PPV, and NPV of the dipstick pH test in differentiating exudative from transudative effusions were 100%, 64.15%, 76.9%, and 100%, respectively, and for different types of exudative effusions were 86.67%, 65.22%, 76.5%, and 78.9%, respectively. Conclusion: The dipstick strip was effectively accurate in detecting transudative from exudative and infectious from noninfectious exudative effusions. Therefore, this accurate, rapid, easy-to-use, and inexpensive tool could be used to distinguish different types of pleural effusion at the bedside, which could be especially helpful in resource-limited settings.