The Value Of PPD Test, Mycodot Three Associated With ESAT-6Test In The Diagnosis Of Culture Negative Tuberculosis

ObjectiveTo explore the value of purified protein derivative (PPD) test, MycoDot Three(TB-CHECK test, TB-DOT test, TB-Ab test) associated with the early secretory antigen6kD induced Interferon-y release response test (ESAT-6test) in the diagnosis of culture negative tuberculosis.Materials and Methods328cases were selected with complete information from Respiratory Medicine and Tuberculosis Department of Henan Provincial Chest Hospital during the period from January2011to February2012,among which106cases were newly diagnosed culture negative tuberculosis,89cases were newly diagnosed culture positive tuberculosis,133cases were other lung diseases.Newly diagnosed culture negative tuberculosis grouprthe group had106cases in total, including65male and41female, age ranging from4to79,averaged34.07±17.69. Patients had typical clinical manifestations and chest X-ray (or chest CT) existed in active signs of tuberculosis,who had been ruled out other non-tuberculous lung diseases. The diagnosis was consistent with culture-negative and active tuberculosis diagnostic criteria of the tuberculosis diagnostic and treatment guidelines which was enacted by the Chinese Medical Association in2001. In order to avoid interference of the test results by treatment, patients didn’t get anti-tuberculosis therapy or get treatment not more than one month.This group was mainly used to evaluate the diagnostic value of the joint detection.Newly diagnosed culture positive tuberculosis group:the group had89cases in total, including51male and38female, age ranging from14to88, averaged41.13±21.06. The diagnosis was in line with international infectious tuberculosis diagnostic criteria. This group was mainly used for the evaluation of the detection methods’sensitivity.Other lung diseases group:The group had133cases in total, including84males and49females, age ranging from4to87, averaged57.72±18.30. There were10cases of small cell lung cancer,36cases of lung adenocarcinoma,20cases of lung squamous cell carcinoma,2cases of large cell lung cancer,1case of schwannoma,20cases of chronic obstructive pulmonary disease,9cases of pneumonia,19cases of bronchiectasis,5cases of lung abscess,8cases of chronic bronchial inflammation and3cases of the other disease. They were confirmed by the relevant examination and ruled out the presence of tuberculosis.This group was used to evaluate the specificity of the detection methods.Statistical methodsUsing spss13.0package to analyze the data, using chi-square test between the count data groups. a=0.05for the test level, if a<0.05, the difference was statistically significant.Results1. The positive rates of PPD test, MycoDot three and ESAT-6test in culture negative tuberculosis group are higher than the non-tuberculosis group, the indicators between the two groups was statistically significant (P<0.05).2. In the PPD test, MycoDot three and ESAT-6test, the diagnostic index of ESAT-6is the highest, which is157.22%and its diagnostic efficiency is the best. Its sensitivity and specificity of culture negative pulmonary tuberculosis are79.78%,77.44%.3. The positive rates of culture negative tuberculosis increase with the increase of joint indicators.The positive rates of the2-links,3-links with ESAT-6test are significantly higher than that without ESAT-6test,the difference is statistically significant (P<0.05). However, the positive rate of the4-links is similar, the difference is not statistically significant P>0.05).4. In the various indicators of joint detection, the diagnostic performance of ESAT-6+PPD+TB-Ab is the best, with highest index152.05%. Its sensitivity and specificity are93.40%,58.65%.ConclusionsMultiple test indicators can improve the diagnostic sensitivity of culture negative tuberculosis. The joint detection of ESAT-6+PPD+TB-Ab is the best.