The auxiliary diagnostic performance of creation tuberculin skin test for mycobacterium tuberculosis compared with QuantiFERON-TB Gold Plus: A diagnostic accuracy study

Abstract

Background

For bacteriologically negative suspected tuberculosis, immunological testing provides important diagnostic evidence. The traditional tuberculin skin test has poor specificity. QuantiFERON-TB Gold Plus (QFT-Plus, the latest generation of Interferon-Gamma Release Assays) and creation tuberculin skin test (C-TST) offer higher specificity and are less affected by non-tuberculous mycobacteria and BCG vaccine. However, the efficacy of QFT-Plus and C-TST in suspected tuberculosis remain unclear. We compared the performance of the QFT-Plus with the C-TST in auxiliary diagnosing tuberculosis in individuals with suspected tuberculosis.

Methods

The subjects were 137 patients suspected of tuberculosis, including 74 pulmonary tuberculosis (PTB) patients and 63 non-active pulmonary tuberculosis. All participants underwent both QFT-Plus and C-TST testing.

Results

The sensitivities of QFT-Plus and C-TST in diagnosing PTB were 93.15 % and 86.49 %, respectively. The specificities of QFT-Plus and C-TST in diagnosing PTB were 40.35 % and 41.27 %, respectively. When QFT-Plus and C-TST were combined, the specificity increased to 58.73 %. The Area Under the Curves of Receiver Operating Characteristic in QFT-Plus and C-TST were 0.79 vs 0.67 (p < 0.05), respectively. In addition, the median IFN-γ level of TB2 tubes in the PTB group of QFT-Plus was significantly higher than that of TB1 tubes.

Conclusions

QFT-Plus and C-TST demonstrated diagnostic value in helping clinicians identify PTB and rule out non-patients to a certain extent, and the two methods had moderate agreement. The combined diagnosis statistically improved the specificity in auxiliary diagnosing PTB. Furthermore, the QFT-Plus appears more advantageous than C-TST for auxiliary diagnosing of tuberculosis.