Effects of sputum bacillary load and age on GeneXpert and traditional methods in pulmonary tuberculosis: a 4-year retrospective comparative study
Abstract Background The purpose of this study was to evaluate the diagnostic value of the GeneXpert® MTB/RIF (Xpert®), Auramine O staining method, and Lowenstein-Jensen medium for bacteriologically confirmed pulmonary tuberculosis and explore the effects of the sputum bacillary load (SBL) and qRT‒PC...
| Main Authors: | , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
BMC
2023-11-01
|
| Series: | BMC Infectious Diseases |
| Subjects: | |
| Online Access: | https://doi.org/10.1186/s12879-023-08832-6 |
| _version_ | 1827604237730709504 |
|---|---|
| author | Kui Li Qianqian Hu Jun Liu Siyi Liu Yingli He |
| author_facet | Kui Li Qianqian Hu Jun Liu Siyi Liu Yingli He |
| author_sort | Kui Li |
| collection | DOAJ |
| description | Abstract Background The purpose of this study was to evaluate the diagnostic value of the GeneXpert® MTB/RIF (Xpert®), Auramine O staining method, and Lowenstein-Jensen medium for bacteriologically confirmed pulmonary tuberculosis and explore the effects of the sputum bacillary load (SBL) and qRT‒PCR threshold cycle (Ct) value on the detection methods. Methods We retrospectively analysed the results in the Department of Infectious Disease for 49 months. The χ2 test was used to compare the performances of each method, receiver operating characteristic curve analysis was used to determine the optimal cut-off values, and the factors associated with a false-negative result from Xpert® were analysed by logistic regression. Results Simultaneous analysis of 980 sputum specimens showed that the positive detection rate of Xpert® did not increase with increasing SBL, and there were differences between the three when SBL ≤ 1 + (all P < 0.05). There was a good negative correlation between the Ct value and the SBL (P < 0.0001). Age was an independent risk factor for false-negative Xpert® results (P = 0.029), and when Ct < 16, the diagnostic sensitivity and specificity were both 100.00%. The optimal cut-off Ct values for resegmentation based on the drug resistance classification were < 18.6, 18.6–34.1, and > 34.1 cycles. Conclusions Xpert® was not affected by SBL but it was by age, and it is more advantageous when SBL ≤ 1 + . The results regarding rifampicin resistance were reliable, and the novel Ct segmentation was a practical and more clinically meaningful classification method for diagnosing rifampicin resistance. These findings will help improve physicians’ ability to accurately diagnose TB. |
| first_indexed | 2024-03-09T05:56:10Z |
| format | Article |
| id | doaj.art-57f6a6aa990c48a9810f58e55a56e339 |
| institution | Directory Open Access Journal |
| issn | 1471-2334 |
| language | English |
| last_indexed | 2024-03-09T05:56:10Z |
| publishDate | 2023-11-01 |
| publisher | BMC |
| record_format | Article |
| series | BMC Infectious Diseases |
| spelling | doaj.art-57f6a6aa990c48a9810f58e55a56e3392023-12-03T12:13:24ZengBMCBMC Infectious Diseases1471-23342023-11-0123111210.1186/s12879-023-08832-6Effects of sputum bacillary load and age on GeneXpert and traditional methods in pulmonary tuberculosis: a 4-year retrospective comparative studyKui Li0Qianqian Hu1Jun Liu2Siyi Liu3Yingli He4Department of Infectious Diseases, The First Affiliated Hospital of Xi’an Jiaotong UniversityLaboratory of Molecular Pathology and Tuberculosis Diseases, Ankang Central HospitalLaboratory of Molecular Pathology and Tuberculosis Diseases, Ankang Central HospitalDepartment of Infectious Diseases, The First Affiliated Hospital of Xi’an Jiaotong UniversityDepartment of Infectious Diseases, The First Affiliated Hospital of Xi’an Jiaotong UniversityAbstract Background The purpose of this study was to evaluate the diagnostic value of the GeneXpert® MTB/RIF (Xpert®), Auramine O staining method, and Lowenstein-Jensen medium for bacteriologically confirmed pulmonary tuberculosis and explore the effects of the sputum bacillary load (SBL) and qRT‒PCR threshold cycle (Ct) value on the detection methods. Methods We retrospectively analysed the results in the Department of Infectious Disease for 49 months. The χ2 test was used to compare the performances of each method, receiver operating characteristic curve analysis was used to determine the optimal cut-off values, and the factors associated with a false-negative result from Xpert® were analysed by logistic regression. Results Simultaneous analysis of 980 sputum specimens showed that the positive detection rate of Xpert® did not increase with increasing SBL, and there were differences between the three when SBL ≤ 1 + (all P < 0.05). There was a good negative correlation between the Ct value and the SBL (P < 0.0001). Age was an independent risk factor for false-negative Xpert® results (P = 0.029), and when Ct < 16, the diagnostic sensitivity and specificity were both 100.00%. The optimal cut-off Ct values for resegmentation based on the drug resistance classification were < 18.6, 18.6–34.1, and > 34.1 cycles. Conclusions Xpert® was not affected by SBL but it was by age, and it is more advantageous when SBL ≤ 1 + . The results regarding rifampicin resistance were reliable, and the novel Ct segmentation was a practical and more clinically meaningful classification method for diagnosing rifampicin resistance. These findings will help improve physicians’ ability to accurately diagnose TB.https://doi.org/10.1186/s12879-023-08832-6Bacillary loadAge factorsGeneXpert® MTB/RIFTuberculosisComparative study |
| spellingShingle | Kui Li Qianqian Hu Jun Liu Siyi Liu Yingli He Effects of sputum bacillary load and age on GeneXpert and traditional methods in pulmonary tuberculosis: a 4-year retrospective comparative study BMC Infectious Diseases Bacillary load Age factors GeneXpert® MTB/RIF Tuberculosis Comparative study |
| title | Effects of sputum bacillary load and age on GeneXpert and traditional methods in pulmonary tuberculosis: a 4-year retrospective comparative study |
| title_full | Effects of sputum bacillary load and age on GeneXpert and traditional methods in pulmonary tuberculosis: a 4-year retrospective comparative study |
| title_fullStr | Effects of sputum bacillary load and age on GeneXpert and traditional methods in pulmonary tuberculosis: a 4-year retrospective comparative study |
| title_full_unstemmed | Effects of sputum bacillary load and age on GeneXpert and traditional methods in pulmonary tuberculosis: a 4-year retrospective comparative study |
| title_short | Effects of sputum bacillary load and age on GeneXpert and traditional methods in pulmonary tuberculosis: a 4-year retrospective comparative study |
| title_sort | effects of sputum bacillary load and age on genexpert and traditional methods in pulmonary tuberculosis a 4 year retrospective comparative study |
| topic | Bacillary load Age factors GeneXpert® MTB/RIF Tuberculosis Comparative study |
| url | https://doi.org/10.1186/s12879-023-08832-6 |
| work_keys_str_mv | AT kuili effectsofsputumbacillaryloadandageongenexpertandtraditionalmethodsinpulmonarytuberculosisa4yearretrospectivecomparativestudy AT qianqianhu effectsofsputumbacillaryloadandageongenexpertandtraditionalmethodsinpulmonarytuberculosisa4yearretrospectivecomparativestudy AT junliu effectsofsputumbacillaryloadandageongenexpertandtraditionalmethodsinpulmonarytuberculosisa4yearretrospectivecomparativestudy AT siyiliu effectsofsputumbacillaryloadandageongenexpertandtraditionalmethodsinpulmonarytuberculosisa4yearretrospectivecomparativestudy AT yinglihe effectsofsputumbacillaryloadandageongenexpertandtraditionalmethodsinpulmonarytuberculosisa4yearretrospectivecomparativestudy |