scholarly journals Clinical Evaluation of the BDProbeTec Strand Displacement Amplification Assay for Rapid Diagnosis of Tuberculosis

1998 ◽  
Vol 36 (9) ◽  
pp. 2766-2768 ◽  
Author(s):  
John S. Bergmann ◽  
Gail L. Woods
Keyword(s):  
Nontuberculous Mycobacteria ◽  
Direct Detection ◽  
Rapid Diagnosis ◽  
Becton Dickinson ◽  
Strand Displacement Amplification ◽  
Predictive Values ◽  
Amplification Assay ◽  
Smear Negative ◽  
Sensitivity Specificity ◽  
Respiratory Specimens

The reliability of the BDProbeTec MTB Test (Becton Dickinson, Sparks, Md.) for direct detection of Mycobacterium tuberculosis in respiratory specimens was evaluated by comparing results to those of conventional mycobacterial culture, with the BACTEC TB 460 and Middlebrook 7H11 biplates. Patients known to have tuberculosis were excluded from analysis. Of 523 specimens from 277 patients, 53 grew a mycobacterium: 24 specimens of M. tuberculosis and 29 specimens of nontuberculous mycobacteria. After initial testing, 42 specimens were positive by the BDProbeTec, for overall sensitivity, specificity, and positive and negative predictive values of 95.8, 96.2, 54.8, and 99.8%, respectively. After resolution of discrepancies, 28 specimens were positive by the BDProbeTec, for overall sensitivity, specificity, and positive and negative predictive values of 100, 99.2, 85.7, and 100%, respectively. These same values were 100, 80.8, 93.4, and 100%, respectively, for smear-positive samples and 100, 99.4, 75.0, and 100%, respectively, for smear-negative specimens.

Evaluation of the Enhanced Amplified Mycobacterium Tuberculosis Direct Test for Direct Detection of Mycobacterium tuberculosis Complex in Respiratory Specimens

1999 ◽  
Vol 123 (11) ◽  
pp. 1101-1103 ◽  
Author(s):  
Michael B. Smith ◽  
John S. Bergmann ◽  
Michelle Onoroto ◽  
Greg Mathews ◽  
Gail L. Woods
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Nontuberculous Mycobacteria ◽  
Direct Detection ◽  
Direct Test ◽  
Tuberculosis Complex ◽  
Predictive Values ◽  
Smear Negative ◽  
Sensitivity Specificity ◽  
Culture Positive ◽  
Respiratory Specimens

Abstract Objective.—To evaluate the performance of the enhanced Mycobacterium Tuberculosis Direct Test (E-MTD), for the direct detection of M tuberculosis complex (MTBC) in respiratory specimens. Design.—Two hundred seventy-four respiratory specimens from 151 patients in respiratory isolation were tested with the E-MTD, and the results were compared with the results of mycobacterial smear, culture, and the earlier form of the test, MTD-1. Results.—Forty-one specimens were culture positive for mycobacteria (20 MTBC and 21 nontuberculous mycobacteria), 23 of which were smear positive (16 MTBC, 7 nontuberculous mycobacteria). Twenty-four specimens were positive by E-MTD, and 21 were positive by MTD-1. Of the 20 MTBC culture-positive specimens, 19 were positive by the E-MTD and 19 were positive by the MTD-1. The remaining specimens were MTBC negative by all methods. After resolution of discrepancies, the sensitivity, specificity, and positive and negative predictive values were 95.2%, 100%, 100%, 99.6% for the MTD-1 and 95.2%, 98.8%, 87.0%, and 99.6%, for the E-MTD. For the E-MTD smear-positive and smear-negative specimens, these same values were 93.8%, 100%, 100%, and 87.5% and 100%, 98.8%, 62.5%, and 100%, respectively. Conclusion.—The results suggest that the E-MTD is a reliable method for the direct detection of MTBC in smear-positive respiratory specimens.

scholarly journals Clinical Evaluation of the BDProbeTec ET System for Rapid Detection of Mycobacterium tuberculosis

2000 ◽  
Vol 38 (2) ◽  
pp. 863-865 ◽  
Author(s):  
John S. Bergmann ◽  
William E. Keating ◽  
Gail L. Woods
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Test Performance ◽  
Direct Detection ◽  
Distinct Advantage ◽  
Predictive Values ◽  
Number Of Patients ◽  
Smear Negative ◽  
Sensitivity Specificity ◽  
Culture Positive ◽  
Respiratory Specimens

The performance of the BDProbeTec ET system (BD Biosciences, Sparks, Md.) for direct detection of Mycobacterium tuberculosis complex (MTBC) in respiratory specimens was evaluated by comparing results to those of conventional mycobacterial culture performed with the BACTEC 460 TB system and Middlebrook 7H11 biplates. Patients known to have been on antituberculous therapy were excluded from the analysis. Of 600 evaluable specimens (4 specimens were excluded from the analysis due to failure of the internal amplification control [IAC]) from 332 patients, 57 grew mycobacteria; 16 were MTBC (from 12 patients), and 41 were nontuberculous mycobacteria. Of the 16 MTBC culture-positive specimens, 12 were smear positive and 4 were smear negative. BDProbeTec ET detected 14 of the 16 MTBC culture-positive specimens, resulting in initial overall sensitivity, specificity, and positive and negative predictive values of 87.5, 99.0, 70.0, and 99.7%, respectively. After resolution of discrepancies by review of medical records and retesting of samples yielding discordant MTBC culture and BDProbeTec ET results, the revised overall sensitivity, specificity, and positive and negative predictive values of the BDProbeTec ET were respectively 93.8, 99.8, 93.8, and 99.8% by specimen and 91.7, 99.7, 91.7, and 99.7% by patient. The BDProbeTec ET System offers the distinct advantage of including an IAC in the specimen well. These data suggest that the test performance is very good, especially for smear-positive samples. However, the number of patients with tuberculosis in our study, especially those with smear-negative disease, was small; therefore, additional studies are needed.

scholarly journals Performance Characteristics of the BDProbeTec System for Direct Detection of Mycobacterium tuberculosis Complex in Respiratory Specimens

1999 ◽  
Vol 37 (1) ◽  
pp. 137-140 ◽  
Author(s):  
Gaby E. Pfyffer ◽  
Pascale Funke-Kissling ◽  
Eva Rundler ◽  
Rainer Weber
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Direct Detection ◽  
Diagnostic Techniques ◽  
Performance Characteristics ◽  
Automated System ◽  
Rrna Gene ◽  
Strand Displacement Amplification ◽  
Predictive Values ◽  
Smear Negative ◽  
Respiratory Specimens

Strand displacement amplification (SDA) technology has been established in a fully automated system known as BDProbeTec. Target sequences of the insertion sequence IS6110 and the 16S rRNA gene are simultaneously amplified, which thus allows the detection of Mycobacterium tuberculosis complex and, as an additional option, of most Mycobacterium species. Detection occurs via a chemiluminescent microwell assay that employs the simultaneous hybridization and capture of SDA products with a biotinylated capture probe and an alkaline phosphatase detector probe. We have evaluated the performance of the BDProbeTec system in detecting M. tuberculosis complex by testing 799 respiratory specimens and comparing the results to those obtained by conventional diagnostic techniques, i.e., microscopy and culture (solid and radiometric media).M. tuberculosis was cultivated from 41 specimens, of which 28 (68.4%) were smear positive and 13 (31.6%) were smear negative. The overall sensitivity of the SDA assay was 97.6% (for smear-positive specimens, 100%; for smear-negative specimens, 92.3%), and specificity was 95.0%. After resolution of the discrepancies by studying the patients’ clinical data, sensitivity and specificity were 97.9 and 96.5%, respectively, and positive and negative predictive values were 63.9 and 99.9%, respectively. These preliminary data demonstrate that the BDProbeTec system has promising performance characteristics with respiratory specimens and that it allows the detection of M. tuberculosis complex within hours.

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

1998 ◽  
Vol 36 (10) ◽  
pp. 3046-3047 ◽  
Author(s):  
Peter Rohner ◽  
Esther I. M. Jahn ◽  
Beatrice Ninet ◽  
Concetta Ionati ◽  
Rainer Weber ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Direct Detection ◽  
Diagnostic Techniques ◽  
Nucleic Acid Amplification Test ◽  
Nucleic Acid Amplification ◽  
Predictive Values ◽  
Amplification Assay ◽  
Sensitivity Specificity ◽  
Culture Positive ◽  
Respiratory Specimens

The LCx MTB amplification assay is a nucleic acid amplification test intended for the direct detection ofMycobacterium tuberculosis complex in respiratory specimens. We evaluated its performance on 2,001 consecutive respiratory specimens; 78 were culture positive for M. tuberculosis. Sensitivity, specificity, and positive and negative predictive values of this assay for all specimens compared to culture results were 88.5, 97.7, 60.5, and 99.5%, respectively. When referred to resolved clinical diagnosis of active tuberculosis, these values improved to 90.2, 98.4, 72.8, and 99.5%, respectively.

scholarly journals Evaluation of the Xpert MTB/RIF Ultra Assay for Direct Detection ofMycobacterium tuberculosisComplex in Smear-Negative Extrapulmonary Samples

2018 ◽  
Vol 56 (9) ◽  
Author(s):  
Daniel Perez-Risco ◽  
David Rodriguez-Temporal ◽  
Ivan Valledor-Sanchez ◽  
Fernando Alcaide
Keyword(s):  
Nontuberculous Mycobacteria ◽  
Direct Detection ◽  
Extrapulmonary Tuberculosis ◽  
High Sensitivity ◽  
Rapid Diagnosis ◽  
Clinical Samples ◽  
Content Type ◽  
Smear Negative ◽  
Culture Positive ◽  
Culture Negative

ABSTRACTThe rapid detection ofMycobacterium tuberculosiscomplex (MTUBC) in clinical samples is essential for successful treatment. New techniques such as real-time PCR have been developed in order to facilitate rapid diagnosis, but their sensitivity is low in extrapulmonary specimens, due to the low bacillary load in such samples. A next-generation assay has recently been developed to try to overcome this limitation. The aim of this study was to analyze the effectiveness of the Xpert MTB/RIF Ultra (GX-Ultra) for the detection of MTUBC DNA in 108 smear-negative extrapulmonary specimens that were MTUBC culture positive. In addition, 40 extrapulmonary culture-negative samples and 20 samples with nontuberculous mycobacteria were tested to evaluate the specificity of the assay. All samples were collected between May 1999 and May 2017. The GX-Ultra detected DNA of MTUBC in 82 extrapulmonary specimens that were MTUBC culture positive (75.9% sensitivity; 95% confidence interval [CI], 66.6 to 83.4%). The assay was negative for all clinical specimens that were MTUBC culture negative and the samples with nontuberculous mycobacteria (100% specificity). Furthermore, two (1.8%) samples presented mutations related to rifampin resistance. The highest sensitivity was obtained in samples of lymph nodes (94.1%) and nonsterile fluids (93.7%), followed by tissue specimens (86.6%), stool material (80%), abscess aspirates (64.7%), and sterile fluids (60.5%). Pleural fluids, one of the least optimal samples for detecting DNA of MTUBC, were GX-Ultra positive in 10/21 (47.6%) of cases. In summary, GX-Ultra showed excellent specificity and high sensitivity in paubacillary specimens, making it a useful tool for rapid diagnosis of extrapulmonary tuberculosis.

scholarly journals Comparison of Enhanced Mycobacterium tuberculosisAmplified Direct Test with COBAS AMPLICOR Mycobacterium tuberculosis Assay for Direct Detection ofMycobacterium tuberculosis Complex in Respiratory and Extrapulmonary Specimens

2000 ◽  
Vol 38 (4) ◽  
pp. 1559-1562 ◽  
Author(s):  
Claudio Scarparo ◽  
Paola Piccoli ◽  
Alessandra Rigon ◽  
Giuliana Ruggiero ◽  
Mariuccia Scagnelli ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Direct Detection ◽  
Diagnostic Technique ◽  
Clinical Samples ◽  
Direct Test ◽  
Predictive Values ◽  
The Difference ◽  
Sensitivity Specificity ◽  
Detection Ofmycobacterium Tuberculosis ◽  
Respiratory Specimens

The new Roche COBAS AMPLICOR Mycobacterium tuberculosisAssay was compared to the Gen-Probe enhanced Mycobacterium tuberculosis Amplified Direct Test (AMTDII). A total of 486 specimens (296 respiratory and 190 extrapulmonary) collected from 323 patients were tested in parallel with both assays. Results were compared with those of acid-fast staining and culture, setting the combination of culture and clinical diagnosis as the “gold standard.” After resolution of discrepant results, the sensitivity, specificity, and positive and negative predictive values for AMTDII were 85.7, 100, 100, and 90.4% for respiratory specimens and 82.9, 100, 100, and 95.5% for extrapulmonary specimens, respectively. The corresponding values for AMPLICOR were 94.2, 100, 100, and 96.6% for respiratory specimens and 85, 100, 100, and 96.1% for extrapulmonary specimens, respectively. No significant differences were observed between the results of both assays or, within each one, between respiratory and extrapulmonary specimens. The difference between AMTDII and AMPLICOR sensitivities was related to the presence of inhibitory samples, which the former assay, lacking an internal amplification control (IAC), could not detect. The overall inhibition rate for the AMPLICOR assay was 3.9% (19 specimens). It is concluded that, although both amplification assays proved to be rapid and specific for the detection of M. tuberculosis complex in clinical samples, AMPLICOR, by a completely automated amplification and detection procedure, was shown to be particularly feasible for a routine laboratory setting. Finally, AMTDII is potentially an excellent diagnostic technique for both respiratory and extrapulmonary specimens, provided that an IAC is included with the assay.

scholarly journals Rapid Diagnosis of Extrapulmonary Tuberculosis by Ligase Chain Reaction Amplification

1998 ◽  
Vol 36 (5) ◽  
pp. 1324-1329 ◽  
Author(s):  
Fredy Gamboa ◽  
José Dominguez ◽  
Eduardo Padilla ◽  
José M. Manterola ◽  
Elena Gazapo ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Lymph Node ◽  
Extrapulmonary Tuberculosis ◽  
Rapid Diagnosis ◽  
Chain Reaction ◽  
Predictive Values ◽  
Reaction Amplification ◽  
Smear Negative ◽  
Rapid Amplification ◽  
Sensitivity Specificity

A rapid amplification-based test for the diagnosis of extrapulmonary tuberculosis, the LCx Mycobacterium tuberculosis Assay from Abbott Laboratories, was evaluated. Results from the LCx M. tuberculosis Assay were compared with those from culture and the final clinical diagnosis for each patient. A total of 526 nonrespiratory specimens from 492 patients were tested. The specimens included urine; feces; lymph node exudates; pleural, cerebrospinal, articular, and ascitic fluids; tissue biopsies; gastric aspirates; purulent exudates; blood; and bone marrow aspirates. After combination of the culture results and the patient’s clinical data, a total of 135 specimens were collected from 122 patients with a diagnosis of extrapulmonary tuberculosis. The sensitivity, specificity, and positive and negative predictive values for the LCx M. tuberculosis Assay were 77.7, 98.7, 95.2, and 93.1%, respectively; these values rose in resolved cases of TB to 78.5, 100, 100, and 93.1%, respectively. For 37 (27.4%) specimens from patients smear positive for the disease and 98 (72.6%) specimens from patients smear negative for the disease, the sensitivities of the LCx M. tuberculosis Assay were 100 and 71.1%, respectively. Statistically significant differences (P < 0.01) in sensitivities were found between culture and the LCx M. tuberculosis Assay. These differences were even greater among smear-negative specimens. The results demonstrate that the LCx M. tuberculosis Assay will provide rapid and valuable information for the diagnosis of extrapulmonary tuberculosis.

scholarly journals Comparative Evaluation of Initial and New Versions of the Gen-Probe Amplified Mycobacterium Tuberculosis Direct Test for Direct Detection of Mycobacterium tuberculosis in Respiratory and Nonrespiratory Specimens

1998 ◽  
Vol 36 (3) ◽  
pp. 684-689 ◽  
Author(s):  
Fredy Gamboa ◽  
Gregorio Fernandez ◽  
Eduardo Padilla ◽  
José M. Manterola ◽  
Joan Lonca ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Direct Detection ◽  
Turnaround Time ◽  
Nucleic Acid Amplification ◽  
Clinical Samples ◽  
Direct Test ◽  
Predictive Values ◽  
Staining Methods ◽  
Sensitivity Specificity ◽  
Respiratory Specimens

We evaluated the initial version of the Amplified Mycobacterium Tuberculosis Direct Test (Gen-Probe) (AMTDT 1) and the new version of AMTDT (AMTDT 2) for the detection of Mycobacterium tuberculosis directly from respiratory and nonrespiratory samples and compared the results with those of culture and staining methods. The assays were applied to 410 respiratory and 272 nonrespiratory samples collected from 515 patients. The combination of the culture results and clinical diagnosis was considered to be the “gold standard.” Ninety-five respiratory specimens were collected from 67 patients with a diagnosis of pulmonary tuberculosis (TB) and 68 nonrespiratory specimens were collected from 61 patients with a diagnosis of extrapulmonary TB. With respiratory specimens, the sensitivity, specificity, and positive and negative predictive values were 83, 100, 100, and 96%, respectively, for AMTDT 1 and 94.7, 100, 100, and 98.4%, respectively, for AMTDT 2. With nonrespiratory specimens, the sensitivity, specificity, and positive and negative predictive values were 83, 100, 100, and 94%, respectively, for AMTDT 1 and 86.8, 100, 100, and 98.4%, respectively, for AMTDT 2. The overall results of AMTDT 1 and AMTDT 2 were concordant for 97% (661 of 682) of the samples. Statistically significant differences in sensitivities were found between AMTDT 1 and AMTDT 2 with respiratory specimens. It was concluded that although both nucleic acid amplification methods are rapid, sensitive, and specific for the detection of M. tuberculosis complex in all types of clinical samples, AMTDT 2 appeared to be more sensitive than AMTDT 1 when applied to smear-negative specimens. In contrast AMTDT 2 is more susceptible than AMTDT 1 to inhibitory substances in the amplification reaction. The turnaround time of AMTDT 2 is shorter (3.5 h) than that for AMTDT 1 (5 h).

scholarly journals Multicenter Evaluation of the Abbott LCxMycobacterium tuberculosis Ligase Chain Reaction Assay

1999 ◽  
Vol 37 (10) ◽  
pp. 3102-3107 ◽  
Author(s):  
Richard Lumb ◽  
Kirsten Davies ◽  
David Dawson ◽  
Robert Gibb ◽  
Thomas Gottlieb ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Grey Zone ◽  
Relative Operating Characteristic ◽  
Assay Sensitivity ◽  
Predictive Values ◽  
Sensitivity Specificity ◽  
The Relationship ◽  
Culture Positive ◽  
Respiratory Specimens ◽  
Australian Hospital

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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