Archived Comments for:
Xpert MTB/RIF assay can be used on archived gastric aspirate and induced sputum samples for sensitive diagnosis of paediatric tuberculosis
Erratum: Abstract (Discussion section) and Conclusions (at the end of the article)
Harleen Grewal, University of Bergen
17 December 2015
The authors note that regrettably, an older version of the Discussion (abstract section) and Conclusions appear in the published paper online.
The correct versions are:
Abstract: Discussion
Confirmatory diagnosis of TB, particularly in children is challenging. In this study we show, that a combination of multiple sampling techniques (GA and IS) and multiple diagnostic tests provide a better diagnostic yield for intrathoracic pulmonary TB in children. Despite testing of the Xpert MTB/ RIF assay on clinical samples stored at −80 °C, the overall sensitivity of Xpert MTB/RIF on samples that were originally smear and -culture positive (for M. tuberculosis) remained high in samples stored for approximately 2 years (650–849 days), beyond which there was an appreciable decrease in the sensitivity of the Xpert MTB/ RIF assay.
Conclusions (at the end of the paper):
The combination of 2 gastric aspirates and 2 induced sputum samples collected on two consecutive days, and three diagnostic methods i.e. smear examination, liquid culture and Xpert MTB/RIF, yielded a high overall TB detection rate. The overall and per patient detection rate of BACTEC-MGIT culture was 24.4 and 46.9 %, respectively. There was no significant difference in the diagnostic yield of samples collected on day 1 and day 2, however, a combination of GA and IS yielded best results. Despite long term storage, the overall sensitivity of Xpert MTB/RIF on smear and culture positive samples was 95.6 %. In smear negative and culture positive samples the sensitivity of Xpert MTB/RIF was 62.5 %. The TB detection rate of smear microscopy, culture and Xpert MTB/RIF assay was also higher in GA samples than in IS samples. To our knowledge, this is the first report which shows that AFB-positive smear and MTB-culture positive samples stored at −80 °C can be tested by the Xpert MTB/RIF assay for up to 2 years without an appreciable loss in sensitivity of the assay.
Erratum: Abstract (Discussion section) and Conclusions (at the end of the article)
17 December 2015
The authors note that regrettably, an older version of the Discussion (abstract section) and Conclusions appear in the published paper online.
The correct versions are:
Abstract: Discussion
Confirmatory diagnosis of TB, particularly in children is challenging. In this study we show, that a combination of multiple sampling techniques (GA and IS) and multiple diagnostic tests provide a better diagnostic yield for intrathoracic pulmonary TB in children. Despite testing of the Xpert MTB/ RIF assay on clinical samples stored at −80 °C, the overall sensitivity of Xpert MTB/RIF on samples that were originally smear and -culture positive (for M. tuberculosis) remained high in samples stored for approximately 2 years (650–849 days), beyond which there was an appreciable decrease in the sensitivity of the Xpert MTB/ RIF assay.
Conclusions (at the end of the paper):
The combination of 2 gastric aspirates and 2 induced sputum samples collected on two consecutive days, and three diagnostic methods i.e. smear examination, liquid culture and Xpert MTB/RIF, yielded a high overall TB detection rate. The overall and per patient detection rate of BACTEC-MGIT culture was 24.4 and 46.9 %, respectively. There was no significant difference in the diagnostic yield of samples collected on day 1 and day 2, however, a combination of GA and IS yielded best results. Despite long term storage, the overall sensitivity of Xpert MTB/RIF on smear and culture positive samples was 95.6 %. In smear negative and culture positive samples the sensitivity of Xpert MTB/RIF was 62.5 %. The TB detection rate of smear microscopy, culture and Xpert MTB/RIF assay was also higher in GA samples than in IS samples. To our knowledge, this is the first report which shows that AFB-positive smear and MTB-culture positive samples stored at −80 °C can be tested by the Xpert MTB/RIF assay for up to 2 years without an appreciable loss in sensitivity of the assay.
Competing interests
None