The value of BAL fluid LDH level in differentiating benign from malignant solitary pulmonary nodules

Purpose Serum lactate dehydrogenase (LDH) concentration is an indicator of tissue injury. It may be locally secreted in some conditions. This study was performed in order to investigate the value of LDH levels in bronchoalveolar lavage fluid (BALF) in the differentiation of a bening, from a malignant solitary pulmonary nodules (SPN) and to assess its relationship with serum LDH levels. Methods The study was a prospective clinical study. It included 59 patients with a SPN. They underwent bronchoscopy with bronchoalveolar lavage (BAL). Both total serum and BAL LDH levels were measured. Results BALF LDH level was increased in all patients with malignant SPN. The mean BALF LDH level was significantly higher in patients with malignant SPN (342.23 +/- 89.98) as compared to the benign ones (17.62 +/- 7.90) (P < 0.001). There was no correlation between BALF LDH and serum LDH level in patients with SPNs (P = 0.595). Conclusion BALF LDH levels are increased in patients with malignant SPN, but had no significant rise in benign SPN. This factor is useful in differentiating the benign SPNs from malignant SPNs.