Abstract: Objective  To explore the clinical value of procalcitonin detection in pulmonary tuberculosis patients complicated with other bacterial infection. Methods  Selected 134 cases of pulmonary tuberculosis patients in the Severe Tuberculosis Department in Guangzhou Chest Hospital from May to September in 2012. Based on their APACHE-Ⅱand acute physiology and chronic health evaluation, they were divided into severe group (51 cases, admitted to the intensive care room, APACHE-Ⅱ score of 19 to 34, with an average of 23.71 points) and mild group (83 cases, admitted into the general ward). Based on the infection situation among these patients, which were divi-ded into pulmonary tuberculosis complicated with pulmonary infection group (61 cases) and pulmonary tuberculosis only group (73 cases). Detected the concentration of procalcitonin (PCT) in their serum.  Results  Severe patients median value of PCT was 2.75 μg/L，P₂₅＝0.52 μg/L， P₇₅＝10.45 μg/L，and that in mild group was 0.11 μg/L,P₂₅＝0.05 μg/L,P₇₅＝0.43 μg/L, of which was significant difference (Mann-Whitney, U=690,P=0). The median value of PCT of patients combined with lung infection was 3.13 μg/L，P₂₅=1.08 μg/L，P₇₅=10.21 μg/L, and that in pulmonary tuberculosis only patients was median 0.07 μg/L，P₂₅=0.05 μg/L， P₇₅=0.23 μg/L, of which was statistically significant difference (Mann-Whitney, U=265,P=0). The PCT concentration of 90.4%(66/73) pulmonary tuberculosis patients was within the range of <0.5 μg/L.Their sensitivity and specificity were 85.2%(52/61),and 96.3%(52/54) respectively，based on an amount of more than 0.675 μg per liter as a critical clinical reference of a patient to be diagnosed with pulmonary infection of pulmonary tuberculosis.  Conclusion  The mea-surement of procalcitonin was benefit for identifying pulmonary tuberculosis patient complicated with lung infection and prognosis, thus guiding the use of antibiotics.

Key words: Tuberculosis, pulmonary/complications, Pneumonia, bacterial, Calcitonin, Protein precursors