Evaluation Of T-SPOT.TB In The Diagnosis Of Tuberculosis

BackgroundIn recent years, with the rapid development of TB basic research, some of the more reliable detection of tuberculosis has already risen up in immunological detection. Especially in recent years, people have developed a new technology - spot test tuberculosis infection of T cells (T-SPOT.TB), which has been recognized in many European countries and been used in clinical diagnosis. But in our country, due to the presence of higher latent tuberculosis infection patients, the method in the diagnosis of tuberculosis remains controversial. Thus, we conducted the following studies to further evaluate the application value of T-SPOT.TB in diagnosis of tuberculosis.ObjectiveThe results of the T-SPOT.TB, serum antibody detection of tuberculosis and tuberculin skin testing in suspected active tuberculosis patients were compared and the comparison of T-SPOT.TB positive result on the number of spots in the active tuberculosis patients and latent tuberculosis infection, to evaluate the application value of T-SPOT.TB in diagnosis of tuberculosis.MethodsFrom March 2013 to November 2013,167 patients 167 patients hospitalized in First Affiliated Hospital of Xinxiang Medical College of suspected tuberculosis patients were prospectively enrolled, T-SPOT.TB, tuberculosis antibody in serum and tuberculin skin test were conducted for detection. Based on laboratory tests, clinical observation and follow-up results for a long time to finalize the diagnosis. The above three test results and the final clinical diagnosis were compared with.the sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, consistent rate, positive predictive value, negative predictive value as the evaluation index.The T-SPOT.TB, and serum antibody tuberculosis, tuberculin skin test were compared respectively. And the impact of age, malnutrition and severe tuberculosis on T-SPOT.TB susceptibility were analized respectively. Statistics of active tuberculosis and latent tuberculosis infection in patients with T-SPOT.TB positive result spots and comparative analysis.Results(1) The sensitivity of T-SPOT.TB, tuberculosis antibody detection, tuberculin skin test were 90%,28%,55%, respectively. T-SPOT.TB respectively compared with the other two detection methods, the difference was statistically significant (P<0.001).(2) The specificity of T-SPOT.TB, tuberculosis antibody test, tuberculin skin test were 81.3%,79.1%,76.9%, respectively. T-SPOT.TB respectively compared with the other two detection methods, the difference was not statistically significant (P>0.05).(3) The positive likelihood ratios of T-SPOT.TB, tuberculosis antibody test, tuberculin skin test were 4.813,1.34,2.38, respectively. Negative likelihood ratios were 0.12,0.91,0.59, respectively.(4) The consistent rates in T-SPOT.TB, tuberculosis antibody test, tuberculin skin test were 84.8%,58.9%,68.2%, respectively. T-SPOT.TB respectively compared with the other two detection methods, the difference was statistically significant (P<0.05).(5) The positive predictive value of T-SPOT.TB, tuberculosis antibody test, tuberculin skin test were 76%,47%,61%, respectively. There is a statistically significant difference compared with tuberculosis antibody detection (P<0.05), no significant difference compared with the tuberculin skin test(P>0.05).(6) The negative predictive value of T-SPOT.TB, tuberculosis antibody test, tuberculin skin test were 93%,62.6%,72.7%,respectively. T-SPOT.TB. respectively compared with the other two detection methods, the difference was statistically significant (P<0.001).(7)There were no significant difference on T-SPOT.TB sensitivity between malnutrition group and no malnutrition group, elderly group and the non-elderly group, severe tuberculosis group and non-severe tuberculosis group(P>0.05).(8) In patients with active tuberculosis and latent tuberculosis infection positive results the median of T-SPOT.TB antigen A spots were 21 and 14, no significant differences between the two (P>0.05), antigen B hole spots in the median were 25 and 3, two were statistically significant difference (P<0.05).ConclusionT-SPOT.TB is a better method for rapid diagnosis of tuberculosis. The negative results can help to exclude active tuberculosis; the positive results for the diagnosis of tuberculosis activity has little significance.