The Value of LDH Level of BAL Fluid in Differentiating Benign from Malignant Solitary Pulmonary Nodules

Background: serum lactate dehydrogenase (ldh) concentrationis an indicator for tissue injury. it may be secreted locallyin many conditions. for the first time, this study was performedto investigate the value of ldh level in bronchoalveolarlavage fluid (balf) in differentiation of benign from malignantsingle pulmonary nodules (spns) and to assess its relationshipwith serum ldh levels.methods: this study was a prospective case-control clinicalstudy. it included 59 patients with a spn and 21 non-smokerhealthy adult volunteers as controls. they underwent bronchoscopywith bal, transbronchial needle aspiration (tbna),and transbronchial biopsy (tbb). both total serum and balldh levels were measured.results: the range of the bal ldh levels in the control groupwas 4,60 -26 miu/ml, in patients with benign nodule was 6 - 83miu/ml, and in those with malignant nodule was 33 -147miu/m!. overall, the mean balf ldh level was significantlyhigher in patients with a malignant pulmonary nodule (85.92 ±28.31) as compared with that of either patients with a benignnodule (19.08 ± 18.35) (p