Efficacy of Acid-Fast Staining, Real-Time Fluorescent PCR, and Immunohistochemical Staining in Diagnosing Pulmonary Tuberculosis

Abstract

Abstract Objective: To evaluate the diagnostic utility of acid-fast staining, real-time fluorescent PCR, and immunohistochemical staining in identifying pulmonary tuberculosis. Methods: Acid fast staining, real-time fluorescence PCR, and immunohistochemical staining were performed on lung tissue samples from 69 tuberculosis patients and 67 non tuberculosis patients to detect Ag85B, ESAT-6, and CFP10.The detection efficiency of each method was compared. Results: Acid-fast staining and real-time fluorescent PCR demonstrated sensitivities of 26.09%,49.28%, both with a specificity of 100%. The sensitivities for Ag85B, ESAT-6,CFP10 were 62.32%, 78.26%,69.57%,while their specificities were 86.57%, 85.07%, 91.04%. The AUC was highest for ESAT-6 (AUC=0.817). Joint antigen analysis revealed that simultaneous positivity for two or three of Ag85B, ESAT-6, CFP10 increased specificity (95.52% to 100%) but decreased sensitivity (49.28% to 62.31%). The presence of any one of the three antigens elevated sensitivity (81.16% to 88.41%) but lowered specificity (68.66% to 77.61%). Specificity reached 100% for concurrent positivity of all three antigens, while a sensitivity of 88.41% was observed for positivity of any one antigen. Conclusion: 1. Real-time fluorescent PCR exhibits higher sensitivity compared to acid-fast staining, though both methods have very high specificity. 2. Immunohistochemical staining for Ag85B, ESAT-6, and CFP10 in lung tissue shows higher sensitivity than real-time fluorescent PCR and provides valuable diagnostic support, particularly in cases where acid-fast staining and PCR are negative. 3. Combined antigen testing enhances the diagnostic accuracy for pulmonary tuberculosis, with simultaneous positivity of all three antigens being crucial for confirming tuberculosis, while their collective negativity is significant in ruling out the disease.