Background: Serum lactate dehydrogenase (LDH) concentration is an indicator of tissue injury. It may be increased in a variety of interstitial diseases and in pulmonary tuberculosis (PTB).
Objective: To investigate the value of LDH levels in bronchoalveolar lavage fluid (BALF) for the diagnosis of active PTB and to assess its relationship with serum LDH levels.
Methods: The study was a prospective clinical study. It included 25 consecutive patients with documented active PTB and 20 healthy adults who underwent bronchoscopy with bronchoalveolar lavage (BAL). Both total serum and LDH levels were measured.
Results: BALF LDH level was increased in all patients with active PTB. The mean BALF LDH level was significantly higher in patients with PTB (198.84+/-88.31 mIU/ml) as compared to controls (14.01+/-8.69 mIU/ml) (p = 0.0001). There was a significant correlation between BALF LDH and serum LDH levels in patients with PTB (r = 0.55, p = 0.006).
Conclusion: BALF LDH levels are not specific and may be increased in many diseases. A very low value (possibly less than 60 mIU/ml) may, on the other hand, be useful to exclude the diagnosis of active PTB.