Clinical diagnostic value of simultaneous amplification and testing for the diagnosis of sputum-scarce pulmonary tuberculosis

Liping Yan,Qing Zhang,Heping Xiao

doi:10.1186/s12879-017-2647-7

Liping Yan, Qing Zhang + Show 1 more

Open Access

https://doi.org/10.1186/s12879-017-2647-7

Copy DOI

Abstract

BackgroundSince 20% of pulmonary tuberculosis (PTB) patients are asymptomatic, the early detection of PTB is a challenge particularly in sputum-scarce patients and diagnostic accuracy based solely on clinical characteristics and chest X-ray/CT scans are not always satisfactory. The AmpSure simultaneous amplification and testing method for the detection of Mycobacterium tuberculosis (SAT-TB assay) is an alternative approach to diagnose PTB. In the present study, we analyzed the usefulness of the SAT-TB assay for PTB diagnosis in sputum-scarce patients.MethodsA total of 840 patients were prospectively enrolled for PTB diagnosis with bronchial alveolar lavage fluid (BALF) used as the samples for the SAT-TB assay. Of these, 536 had a definite diagnosis of PTB confirmed by positive microbiology culture, or clinical diagnosis of active PTB following anti-TB treatment with a favorable response.ResultsThe SAT-TB assay showed a 76.44% agreement with the culture test. The sensitivity and specificity of the SAT-TB assay were 50.75% and 94.73%, respectively. The sensitivity of SAT-TB was significantly higher than that of BALF cultures (21.64%) (X2 = 49.1503; P < 0.001) and smears (4.48%) (X2 = 175.2315; P < 0.001). The specificity of SAT-TB was slightly lower than that of BALF cultures (98.25%) (X2 = 2.0727; P = 0.150) and smears (98.25%) (X2 = 2.0727; P = 0.150). The accuracy rates were 63.87% for SAT-TB, 44.50% for BALF cultures and 29.84% for BALF smears.ConclusionThe high accuracy of the SAT-TB assay indicated that active PTB is present and anti-TB treatment is strongly recommended regardless of smear and culture test results for sputum scarce active PTB suspected patients when BALF SAT-TB is positive.

Highlights

Since 20% of pulmonary tuberculosis (PTB) patients are asymptomatic, the early detection of PTB is a challenge in sputum-scarce patients and diagnostic accuracy based solely on clinical characteristics and chest X-ray/computed tomography (CT) scans are not always satisfactory
SAT-TB detected 164 PTB cases (39.05%), which were negative for bronchial alveolar lavage fluid (BALF) culture tests (Table 1)
It is worth mentioning that we choose the sputum scare patients, not all TB patients and SAT-TB detected 164 PTB cases (39.05%), which were negative for BALF culture tests in this study

Summary

Introduction

Since 20% of pulmonary tuberculosis (PTB) patients are asymptomatic, the early detection of PTB is a challenge in sputum-scarce patients and diagnostic accuracy based solely on clinical characteristics and chest X-ray/CT scans are not always satisfactory. The AmpSure simultaneous amplification and testing method for the detection of Mycobacterium tuberculosis (SAT-TB assay) is an alternative approach to diagnose PTB. We analyzed the usefulness of the SAT-TB assay for PTB diagnosis in sputum-scarce patients. Only 3.0 million were bacteriologically confirmed [1] and the prevalence of asymptomatic PTB patients has been reported to be as high as 49% in China [2]. Simultaneous amplification and testing methods for detection of MTBC (SAT-TB assay) is a novel molecular technique intended for point-of-care testing for TB. It combines the technologies of nucleic acid isolation, real-time fluorescence simultaneous isothermal RNA amplification and

Methods

Results

Conclusion