RESUMEN
Total and placental alkaline phosphatases were estimated in serum, bronchoalveolar lavage and pleural fluid of 40 patients with different aetiologies of pleural effusion [20 malignant, 15 tuberculous and 5 transudative] in a trial to evaluate its possible diagnostic role. The results showed that serum, bronchoalveolar lavage and pleural fluid total and placental alkaline phosphatases were significantly higher [P < 0.01] in patients with exudative effusion [malignant and tuberculous] when compared with those of transudative or control group. This rise was more marked [P < 0.01] in smoker than non smoker. There was a statistically significant differences [P < 0.001] in the mean values of pleural fluid total and placental alkaline phosphatases between exudative and transudative groups with no overlap in the individual values estimation of pleural fluid alkaline phosphatase [total and placental] is helpful parameter in differentiating exudative from transudative effusion. Local and systemic alkaline phosphatases could be considered as a tissue injury marker. Smoking raises alkaline phosphatases [total and placental]