تعيين ميزان آلكالين فسفاتاز مايع پلور در افتراق بين پلورال افيوژن اگزودا از ترانزودا

Use of pleural alkaline phosphatase content in distinguishing between exudative and transudative effusions

Introduction: Pleural effusion occurs in variety of abnormalities. Its traditional classification as transudates or exudates is useful, differentiation between transudates and exudates is the first diagnostic approach of a patient with pleural effusion. This study evaluates usefulness of pleural alkaline phosphatase (PAP) level for distinguishing between oxidative and transudative effusion and also differentiates tuberculous from malignant effusion based on the level of PAP. Material and Methods: We studied 100 patients with pleural effusion who referred to Ghaem Hospital; Mashhad University of Medical Sciences during a period of one year. All patients underwent diagnostic thoracentesis. The level of pleural fluid glucose, protein, lactate dehydrogenase(LDH), cholesterol,alkaline phosphatase were measured. We considered the threshold level of 20IU for PAP in differentiating transudates from exudates. Results: Among 100 patients with pleural effusion, 43 patients had exudative (tuberculous), 37 had exudative (malignant), and 20 had transudative effusion due to congestive heart failure (CHF). Mean value of PAP in transudative effusion, exudative tuberculous and malignant effusion were: 15.4 ± 3.5, 51.58 ± 4.47 and 79.13 ± 24.22 respectively. The difference between mean value of PAP in transudative and exudative effusion was statistically significant (p<0.001). Sensitivity, specificity and efficiency of these criteria were: 96,7 %, 86 % and 94 % respectively. Conclusion: Determination of the PAP level is usefiil and highly effective for distinguishing between transudates and exudates and should be included in biochemical analysis of pleural effusions. Our study did not show significant difference between mean value of PAP in tuberculous and malignant exsudative effusions.