Abstract:

Objective To evaluate the effect of two molecular diagnostic tests (GeneXpert Assay and Isothermal Amplification Technology) on improving the pathogenic positive rate for detection of tuberculosis.Methods Information of active tuberculosis (TB) patients in 23 Counties (Districts) in Jiangsu Province using GeneXpert technology (As Class A) and 46 Counties (Districts) using Isothermal Amplification Technology (As Class B) in 2018 (except for simple pleurisy), and the total number of patients diagnosed as active pulmonary tuberculosis was obtained from China Disease Prevention and Control TB Special Reporting System. The suspected tuberculosis patients from two classes of Counties (Districts) were detected by sputum smear first, and the negative patients were detected by molecular diagnostic test. The L-J solid Roche culture was used simultaneously, and the TB patients were diagnosed by radiography, immunology and clinical symptoms. The pathogenic positive patients means detected by sputum smear, sputum culture or molecular biology,at least one technology positive (molecule detection positive and culture positive patients were included in the positive number of molecule detection, not duplicate record in the number of culture positive patients), obtains the number of pathogenic positive patients from two kinds of counties (districts) in 2018, as well as three kinds of technology positive patients, and compared with 2015 (when the application of molecular biology technology had not yet begun.Results The pathogenic positive rate was increased from 27.8% to 52.9% in the class A and from 33.0% to 50.6% in the class B. There was significant differences in pathogenic positive rates between the two types of Counties (Districts) in 2015 and 2018 (χ ²=1270.00, P=0.000; χ ²=860.00, P=0.000); the pathogenic positive rates of the two classes of Counties (Districts) in 2015 and 2018 were compared, respectively. The pathogenic positive rates of in the class B in 2015 were higher than those of the class A, and the difference was statistically significant. (In 2018, the pathogenic positive rate in the class A was significantly higher than that in the class B (χ ²=10.60, P=0.001). In 2018, 8176 active pulmonary TB patients were diagnosed in the class A. Among them, 4327 were pathogenic positive (including 3117 smears, 116 sputum cultures and 1094 GeneXpert techniques). The pathogenic positive rate was 52.9% (38.1% smears, 1.4% sputum cultures and 13.4% GeneXpert techniques). The positive rate of GeneXpert technique was accounted for 13.4% of the total pathogenic positive cases. The ratio was 25.3% (1094/4327); 12196 patients with active pulmonary tuberculosis were diagnosed in B counties (districts). Among them, 6171 patients (including 4823 smears, 461 sputum cultures and 887 Isothermal Amplification Technology) were pathogenic positive, with 50.6% (39.5% smears, 3.8% sputum cultures and 7.3% Isothermal Amplification Technology), respectively. The positive rate of technical test was 14.4% (887/6171). Conclusion GeneXpert and Isothermal Amplification Technology can improve the pathogenic positive rate of TB to a certain extent, and both of them are fast and safe. The appropriate molecular biological detection technology can be selected and popularized in County (District) level tuberculosis laboratories according to local conditions.

Key words: Tuberculosis, Molecular biology, Nucleic acid probes, Clinical laboratory tests, Quality Improvement, Evaluation studies