Rapid Diagnosis of Pulmonary Tuberculosis with the LCx
            <i>Mycobacterium tuberculosis</i>
            Assay and Comparison with Conventional Diagnostic Techniques

Rohner, Peter; Jahn, Esther I. M.; Ninet, Béatrice Alice Bescher; Ionati, Concetta; Weber, Rainer; Auckenthaler, Raymond; Pfyffer, Gaby E.

doi:10.1128/jcm.36.10.3046-3047.1998

Cited by 17 publications

(4 citation statements)

References 10 publications

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“…After resolution of discrepant results, the sensitivity, specificity, PPV, and NPV for respiratory specimens were 70.2, 99.9, 98.9, and 98.0%, respectively. These findings agree with previous evaluations of the LCx assay, which reported values of 77.1 to 90.2, 98.4 to 100, 72.8 to 100%, and 90.5 to 99.5%, respectively (3,20,24,28,31,36,39,45). The assay sensitivities for smear-positive and smear-negative respiratory specimens were 98.5 and 41.5%, respectively (Table 3).…”

Section: Discussionsupporting

confidence: 91%

“…The present study has attempted to avoid these biases. Consecutive samples submitted to the participating laboratories were tested; the sample cohort was not enriched with positive samples; hence, the prevalence of culturepositive samples was relatively low (i.e., 6.5%) and the sensitivity of the present study is among the lower of published estimates (3,20,24,28,31,36,39,45). Furthermore, an average of only 1.6 specimens were collected per patient, and the 152 culture-positive specimens were collected from 98 patients (for 94% of these patients three or fewer samples were collected, with an average of 1.5 specimens collected from each patient).…”

Section: Discussionmentioning

confidence: 69%

“…Studies have also varied in their handling of discrepant results. Several evaluations have defined culture-negative, LCx assay-positive specimens from patients on antituberculosis treatment as having false-negative culture results (3,18,20,24,36,39). At present, there is no clinical utility in detecting MTBC DNA or RNA in specimens from currently (or previously) treated patients.…”

Section: Discussionmentioning

confidence: 99%

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Multicenter Evaluation of the Abbott LCx Mycobacterium tuberculosis Ligase Chain Reaction Assay

et al. 1999

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Four Australian hospital laboratories evaluated the performance of the Abbott LCx Mycobacterium tuberculosis assay with 2,347 specimens (2,083 respiratory and 264 nonrespiratory specimens) obtained from 1,411 patients. A total of 152 specimens (6.5%) were culture positive for Mycobacterium tuberculosis complex (MTBC); of these, 79 (52%) were smear positive. After resolution of discrepant data, the overall sensitivity, specificity, and positive and negative predictive values for the LCx assay were 69.7, 99.9, 99.1, and 97.7% respectively. For smear-positive respiratory specimens that were culture positive for MTBC, the values were 98.5, 100, 100, and 98.4%, respectively, while the values for smear-negative respiratory specimens were 41.5, 99.9, 96.4, and 98%, respectively. Relative operating characteristic curves were constructed to demonstrate the relationship between sensitivity and specificity for a range of possible cutoff values in the LCx assay. These graphs suggested that the assay sensitivity for respiratory samples could be increased from 70.2 to 78.6%, while the specificity would be reduced from 99.9 to 99.4% by inclusion of a grey zone (i.e., LCx assay values of between 0.2 and 0.99). An algorithm is presented for the handling of specimens with LCx assay values within this grey zone.

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Section: Discussionsupporting

confidence: 91%

Section: Discussionmentioning

confidence: 69%

Section: Discussionmentioning

confidence: 99%

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Multicenter Evaluation of the Abbott LCx Mycobacterium tuberculosis Ligase Chain Reaction Assay

et al. 1999

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“…However, only 61.2% of the data sets reported the smear‐negative samples as positive. This lack of sensitivity with smear‐negative samples has also been reported by other authors [15–17]. In smear‐positive samples, a NAT improves diagnosis only by rapid further identification of the mycobacteria visible by microscopy, i.e., ‘tuberculosis or non‐tuberculosis’, rather than improved sensitivity.…”

Section: Discussionsupporting

confidence: 62%

Multicentre quality control study for detection of Mycobacterium tuberculosis in clinical samples by nucleic amplification methods

Noordhoek

Mulder

Wallace³

et al. 2004

Clinical Microbiology and Infection

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The aim of this study was to evaluate the laboratory performance of nucleic acid amplification tests (NATs) for detection of the Mycobacterium tuberculosis complex. A proficiency panel consisting of eight sputum specimens and four specimens diluted in phosphate-buffered saline (PBS) was sent to 82 laboratories in 23 countries by the Quality Control for Molecular Diagnostics (QCMD) TB programme. The performance of different NATs was analysed in combination with a questionnaire on the applied methods. Seventy-eight participants (95.2%) contributed a total of 85 evaluable data sets. The percentage of correct results on the eight sputum samples was 86.3% (586/679). Of the sputum specimens considered as 'smear-negatives' (650 CFU/250 micro L), only 61.2% (104/170) were reported positive. The percentage of correct results for the three scored PBS samples was 75.7% (193/255). The total number of false-positive results was 11 (4.3%); these were reported for seven (8.2%) of the 85 data sets. In 32 (37.6%) data sets an 'in-house' NAT method was used, and in 53 (62.4%) sets a commercial assay was tested. The percentage of data sets achieving correct results on all sputum samples was 35.3% and 37.8%, respectively. For the PBS samples this was 45.8% and 41.5%. Overall, the results of this study demonstrated that the performance of NATs for the detection of M. tuberculosis has improved since previous studies. The percentage of false-positives has decreased considerably. However, a large number of procedures still lack sufficient sensitivity for application to smear-negative samples.

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Ligase Chain Reaction

Wilson

2002

Wiley Encyclopedia of Molecular Medicine

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Rapid Diagnosis of Pulmonary Tuberculosis with the LCx Mycobacterium tuberculosis Assay and Comparison with Conventional Diagnostic Techniques

Cited by 17 publications

References 10 publications

Multicenter Evaluation of the Abbott LCx Mycobacterium tuberculosis Ligase Chain Reaction Assay

Multicenter Evaluation of the Abbott LCx Mycobacterium tuberculosis Ligase Chain Reaction Assay

Multicentre quality control study for detection of Mycobacterium tuberculosis in clinical samples by nucleic amplification methods

Ligase Chain Reaction

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