Serum alkaline phosphatase may play a role in the differential diagnosis of sarcoidosis and tuberculosis

Reaching the differential diagnosis of tuberculosis and sarcoidosis can be difficult due to granulomatous inflammation. Determining alkaline phosphatase (ALP) activity in serum for the differential diagnosis of tuberculosis and sarcoidosis. This study comprised 104 acid-fast bacilli (AFB) positive patients with pulmonary tuberculosis, 90 patients with biopsy-proven sarcoidosis and 43 healthy controls were included. ALP activity was measured at the first admission of the patients. There was a significant difference between the tuberculosis and the control (p= 0.03). Also, there was a significant difference between the tuberculosis and sarcoidosis (p= 0.034 ) According to the comparison of tuberculosis and sarcoidosis, the cut-off value was determined as 71.50 IU/L, which had sensitivity of 80%, specificity of 51%, PPV of 66%, NPV of 69%, accuracy of 67%, and the AUC was 0.728. ALP, as a little-known marker for tuberculosis and sarcoidosis, was increased in the pulmonary tuberculosis compared with the sarcoidosis. As such, it may be a useful tool for the differentiation of tuberculosis and sarcoidosis.