Diagnostic Value Of MLR Combined With Gene-Xpert MTB/RIF For Smear Negative Tuberculosis

Objective:The value of peripheral blood monocyte/lymphocyte ratio(MLR)combined with Gene-Xpert MTB/RIF in the diagnosis of smeared negative pulmonary tuberculosis.Methods:In this study,114 patients with suspected smear-negative pulmonary tuberculosis who underwent Gene-Xpert MTB/RIF testing were admitted to the respiratory Department of Chest Hospital from May 2021 to December 2022,and 57 patients with simple pneumonia and 67 healthy subjects admitted to the Fourth Affiliated Hospital of Nanchang University during the same period were included.Clinical data,including neutrophil count,monocyte count,lymphocyte count,albumin,height,weight,age,sex,etc.,were collected,and monocyte lymphocyte ratio(MLR),neutrophil lymphocyte ratio(NLR),prognostic nutrition index(PNI)were calculated.According to the final diagnosis results,the data were divided into negative smeared pulmonary tuberculosis group(Yin cultivation group and Yang cultivation group),simple pneumonia group and healthy physical examination group.Receiver operating curve(ROC)was used to evaluate the diagnostic efficacy of peripheral blood MLR,NLR and PNI for negative smeared pulmonary tuberculosis.The diagnostic efficacy of Gene-Xpert MTB/RIF in the diagnosis of smear-negative pulmonary tuberculosis was calculated.Result:1.There were significant differences in gender,age and BMI among patients in different groups,and there were also differences in prognostic nutritional index between patients in the pulmonary tuberculosis group and the pneumonia group by calculation.In addition,patients in the pulmonary tuberculosis group had lower PNI,so there were more males in the pulmonary tuberculosis group,with lower body mass index and poorer nutrition,requiring more nutritional support;2.Compared with the serological indicators of the three groups,there was no statistical difference in neutrophil count among the three groups,but there was a statistically significant difference between the comparison groups of lymphocytes and monocytes.In addition,there was a significant decrease in lymphocyte count and a high monocyte count in the pulmonary tuberculosis group,while there was no statistical difference between the simple pneumonia group and the healthy physical examination group.Mononuclear cells and neutrophils were high,but they were basically within the normal range and did not have special diagnostic significance.3.There were also significant differences between MLR and NLR among the three groups,and the two indexes in the pulmonary tuberculosis group were higher.ROC curve calculation showed that MLR had higher sensitivity and specificity for the diagnosis of pulmonary tuberculosis,and its AUC value was 0.7428(the area under the curve of NLR and PNI were 0.6239 and 0.6255,respectively).When the cutoff value was 0.2630,the sensitivity was up to 91.55%,and the specificity was46.00%,which could provide a basis for the identification of tuberculosis,especially smeared tuberculosis.4.In the test of Gene-Xpert in the experimental group and the control group,the diagnostic sensitivity and specificity of Gene-XPert for smear-negative tuberculosis were only 36.62% and 97.67%.When the positive mycobacterium tuberculosis culture was used as the gold standard,the sensitivity of the detection was increased to53.85%,and the specificity was reduced to 76.00%,indicating that the gene detection had great value in the diagnosis of tuberculosis,and the sensitivity was higher for the positive mycobacterium tuberculosis patients.5.MLR cutoff value ≥0.2630 was selected as the positive diagnostic criteria,and the sensitivity and specificity of combined Gene-Xpert detection for diagnosis of smear-negative tuberculosis were 92.96% and 97.67%,respectively.The combination of the two could increase the sensitivity and specificity of diagnosis of tuberculosis.Conclusion:1.The sensitivity and specificity of MLR are higher in the identification of tuberculosis,and the increase of MLR level can be a potential indicator of the diagnostic positive rate of smeared negative tuberculosis;2.Genetic detection is of great value in the diagnosis of tuberculosis,especially for culture-positive tuberculosis patients;3.MLR combined with Gene-Xpert MTB/RIF in the diagnosis of smear-negative tuberculosis can increase the sensitivity and specificity of the diagnosis of tuberculosis and improve the detection rate.