The Diagnostic Value Of T-SPOT. TB Tests To Suspected Tuberculosis Patients In Different BMI Groups

[Objectives]Discuss the diagnostic value of T-SPOT.TB tests to suspected tuberculosis patients in different BMI groups,and analysis whether there is a correlation of BMI and routine blood lymphocyte count,routine blood mononuclear cell counts and mycobacterium tuberculosis specific T lymphocyte count of blood T-SPOT.TB tests[Methods]1.Retrospective analysis 240 cases suspected pulmonary tuberculosis who were hospitalized in Department of Respiratory Medicine of the First Affiliated Hospital of Kunming Medical University on January 1,2015 to December 31,2016 and taked the T-SPOT.TB test.The examination of mycobacterium tuberculosis was completed after admission,such as acid-fast bacillus smear and the mycobacterium tuberculosis culture of sputum and bronchoalveolar,histopathological examination of mycobacterium tuberculosis and so on.there were 138 cases of tuberculosis and 102 cases of non-tuberculosis patients in the end.The subjects were divided into three groups by BMI:group A(the thin group BMI<18.6kg/m2),group B(the normal group 18.6?BMI?22.9kg/m2),and group C(the overweight and obese group BMI?23kg/m2).2.The patient's discharge diagnosis,age,gender,height,weight,body mass index,the results of T-SPOT.TB test,the lymphocyte count and mononuclear number of the blood which were checked for the first time after admission,compare the results of T-SPOT.TB test with the diagnosis,and then analyse the diagnostic effectiveness of T-SPOT.TB test.Gender count data by chi-square test,other counting data adoption rate and composition ratio representation,Youden index and diagnostic accuracy is compared between group,P<0.05 was statistically significant.Basic description measurement data to normal distribution or similar to normal distribution,use the mean +/-standard deviation,the matching t test was used in the group,two or two comparisons of the mean of multiple samples in the variance analysis were compared.[Results]The study included 240 subjects,include 153 men and 87 women,The sex ratio was 1.76,The youngest is 18 years old,the oldest is 87 years old,with an average age of 49.41±18.81.Group A 45,group B 162,group C 33.There was no statistical difference between the ages of the three groups and gender of the three groups.T-SPOT.TB test were highly sensitive and specific to group B,while group A and C were lowerly sensitive and specific.The blood T lymphocyte numbers of group C were higher than those in group A and lower than those in group B,only the difference between group A and group B was statistically significant by comparison among groups.The blood monocytes numbers of group C were higher than those ingroup A and lower than those in group B,by comparison among groups the difference between group A and group B was statistically significant,and the difference between group C and group B was statistically significant.There were no statistically significant differences in the sensitivity T lymphocyte number such as A hole spots and B hole spots of patients in the three groups,and the number of A hole spots in the three groups was statistically different,and the group B was greater than group A and group C.There were statistically significant differences in the number of B hole spots in the three groups too,and group B was greater than group A and group C.[Conclusion]1.The patients with thin,overweight and obese can reduce sensitivity,specificity,positive predictive value and negative predictive value of T-SPOT.TB test,which leads to the accuracy of T-SPOT.TB test to the diagnosis of tuberculosis decrease;2.The body's immune function disorder in the thin,the overweight and obese patients,and it causes allergenic T lymphocytes decreased after tuberculosis infection,and release less gamma interferon,so A hole spots and B hole spots were reduced in T-SPOT.TB results;3.The reduction of T lymphocytes in thin patients was even more pronounced,leading to the decline in the value of TB diagnosis in the T-SPOT.TB trial;4.Patients with higher mononuclear cells,A hole spots and B hole spots are high in T-SPOT.TB results.