Comparison of PCR and tuberculin skin test for TB diagnosis in children

Background: Diagnosis of TB in children is difficult due to theless specific symptoms and difficulties in obtaining the specimen. Tuberculin skin test has been used widely to investigate theinfection of TB in children, but it still has the weakness in certainsubjects. Polymerase Chain Reaction (PCR) is currently used tosupport the diagnosis TB, but it still limited data in children. Objective: To compare the accuracy of PCR and TST in diagnosis TBin children. Method: It was a diagnostic study to evaluate the accuracy of PCR in diagnosing childhood TB. The patient aged 0–15 years wererecruited and evaluated for TB. The subjects did the TST, PCR and AFB direct smear and culture. The specimens were obtained fromsputum or gastric lavage. The gold standard was the positive resultof smear and/or culture of Mycobacterium tuberculosis. Result: One hundred and twenty-five subjects were evaluated forTB. The positive AFB and/or culture were found in 27 subjects.Among 27 confirmed TB patients, TST were positive in 16 subjects (sensitivity 59.3%) while PCR were positive in 15 subjects (sensitivity55.6%). The specificity, PPV and NPV of TST were 56.1%, 27.1% and83.3% respectively while the specificity, PPV and NPV of PCR were 63.3%, 36.6% and 83.8% respectively. Conclusion: For diagnosing TB in children, PCR did not show thesuperiority in diagnostic values compared to Tuberculin Skin Test.The larger study in children is needed to have the more powerfulresult