Diagnostic Value Of BALF Xpert MTB/RIF And PCR Reverse Dot Hybridization In Smear-Negative Pulmonary Tuberculosis

Objective:To compare the value of BALF Xpert MTB/RIF assay with PCR reverse dot hybridization for the diagnosis of smear PTB,in order to find a better method for the diagnosis of smear PTB.Methods:Two hundred patients with suspected pulmonary tuberculosis admitted to the respiratory medicine and tuberculosis wards from June 2021 to January 2023 were screened in strict accordance with the inclusion and exclusion criteria,and patients with suspected PTB who met the study criteria were included in the study,all patients underwent bronchoscopy,and BALF was retained and sent for examination,and those with smear-negative pulmonary tuberculosis were finally identified as the observation group and those with non-tuberculosis as the control group.were included in the statistical analysis.The sensitivity,specificity,positive predictive value,negative predictive value,Yordon index,and area under the curve of the two assays were calculated to evaluate the value of BALF Xpert MTB/RIF assay and PCR reverse dot hybridization for the diagnosis of smear-negative PTB.Results:A total of 200 patients with suspected pulmonary tuberculosis were included in the study,including 137 cases in the tuberculosis group(56 positive and 81 negative cases by BALF Xpert MTB/RIF;41 positive and 96 negative cases by PCR reverse dot hybridization;17 positive and 120 negative cases by MGIT90 liquid culture)and 63 cases in the non-tuberculosis group(1 positive and 62 negative cases by BALF Xpert MTB/RIF;3 positive and 60 negative cases by PCR reverse dot hybridization;11 positive and 52 negative cases by MGIT90 liquid culture).MTB/RIF test was positive in 1 case and negative in 62 cases;PCR reverse dot hybridization was positive in 3 cases and negative in 60 cases;MGIT90 liquid culture was positive in 11 cases and negative in 52 cases).The sensitivity of BALF Xpert MTB/RIF assay was 76.7%,the specificity was 58.7%,the Yordon index was 0.364,and the AUC was 0.682 in the tuberculosis group;the sensitivity of PCR reverse dot hybridization assay was 70.7%,the specificity was 55.6%,the Yordon index was 0.263,and the AUC was 0.631 in the non-tuberculosis group.The sensitivity of BALF Xpert MTB/RIF assay in the non-tuberculosis group was 91.7%,the specificity was 54.4%,the Yordon index was 0.461,and the AUC was 0.730;the sensitivity of PCR reverse dot hybridization assay was 78.6%,the specificity was 53.6%,the Yordon index was 0.322,and the AUC was 0.661.The P < 0.05,which were statistically significant.The BALF Xpert MTB/RIF assay has more diagnostic value than PCR reverse dot hybridization technique in the diagnosis of coated PTB.Conclusion:1.the Xpert MTB/RIF assay and the PCR reverse dot hybridization technique were more diagnostic than the BACTEC MGIT 960 rapid liquid culture in terms of positivity,sensitivity,and specificity for smear-negative TB.2.the Xpert MTB/RIF had the highest sensitivity among the three diagnostic methods for bacillary-negative TB(Xpert MTB/RIF,PCR reverse dot hybridization,and BACTEC MGIT 960 rapid liquid culture)and was more diagnostic than the PCR reverse dot hybridization technique.technique,BACTEC MGIT 960 rapid liquid culture)with the highest sensitivity and more diagnostic value than PCR reverse dot hybridization technique in the diagnosis of smear-negative TB.