title: Analytical and Clinical Evaluation of the Epistem Genedrive Assay for Detection of Mycobacterium tuberculosis.
abstract: The Epistem Genedrive assay rapidly detects the Mycobacterium tuberculosis omplex from sputum and is currently available for clinical use. However, the analytical and clinical performance of this test has not been fully evaluated. The analytical limit of detection (LOD) of the Genedrive PCR amplification was tested with genomic DNA; the performance of the complete (sample processing plus amplification) system was tested by spiking M. tuberculosismc(2)6030 cells into distilled water andM. tuberculosis-negative sputum. Specificity was tested using common respiratory pathogens and nontuberculosis mycobacteria. A clinical evaluation enrolled adults with suspected pulmonary tuberculosis, obtained three sputum samples from each participant, and compared the accuracy of the Gene drive to that of the Xpert MTB/RIF assay using M. tuberculosiscultures as the reference standard. The Genedrive assay had an LOD of 1 pg/μl (100 genomic DNA copies/reaction). The LODs of the system were 2.5 × 10(4)CFU/ml and 2.5 × 10(5)CFU/ml for cells spiked into water and sputum, respectively. False-positiverpoBprobe signals were observed in 3/32 (9.4%) of the negative controls and also in few samples containing Mycobacterium abscessus,Mycobacterium gordonae, o rMycobacterium thermoresistibile In the clinical study, among 336 analyzed participants, the overall sensitivities for the tuberculosis case detection of Gene drive, Xpert, and smear microscopy were 45.4% (95% confidence interval [CI], 35.2% to 55.8%), 91.8% (95% CI, 84.4% to 96.4%), and 77.3% (95% CI, 67.7% to 85.2%), respectively. The sensitivities of Gene drive and Xpert for the detection of smear-microscopy-negative tuberculosis were 0% (95% CI, 0% to 15.4%) and 68.2% (95% CI, 45.1% to 86.1%), respectively. The Genedrive assay did not meet performance standards recommended by the World Health Organization for a smear microscopy replacement tuberculosis test. Epistem is working on modifications to improve the assay.
authors: Division of Infectious Diseases, Center for Emerging Pathogens, Rutgers-New Jersey Medical School, Rutgers Biomedical & Health Sciences, Newark, New Jersey, USA.
authors: Shubhada
authors: S
authors: Shenai
authors: Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
authors: Derek T
authors: DT
authors: Armstrong
authors: Foundation for Innovative New Diagnostics, Geneva, Switzerland.
authors: Eloise
authors: E
authors: Valli
authors: Foundation for Innovative New Diagnostics, Geneva, Switzerland.
authors: David L
authors: DL
authors: Dolinger
authors: Infectious Disease Institute and Makerere University, Kampala, Uganda.
authors: Lydia
authors: L
authors: Nakiyingi
authors: Universidade Federal do Espirito Santo, Vitoria, Brazil.
authors: Reynaldo
authors: R
authors: Dietze
authors: Centro de Referência Helio Fraga, FIOCRUZ, Rio de Janeiro, Brazil.
authors: Margareth Pretti
authors: MP
authors: Dalcolmo
authors: University of Cape Town and National Health Laboratory Service, Cape Town, South Africa.
authors: Mark P
authors: MP
authors: Nicol
authors: University of Cape Town and National Health Laboratory Service, Cape Town, South Africa.
authors: Widaad
authors: W
authors: Zemanay
authors: Johns Hopkins University School of Medicine, Baltimore, Maryland, USA Infectious Disease Institute and Makerere University, Kampala, Uganda.
authors: Yuka
authors: Y
authors: Manabe
authors: Universidade Federal do Espirito Santo, Vitoria, Brazil.
authors: David Jamil
authors: DJ
authors: Hadad
authors: Universidade Federal do Espirito Santo, Vitoria, Brazil.
authors: Patricia
authors: P
authors: Marques-Rodrigues
authors: Universidade Federal do Espirito Santo, Vitoria, Brazil.
authors: Moises
authors: M
authors: Palaci
authors: Universidade Federal do Espirito Santo, Vitoria, Brazil.
authors: Renata L
authors: RL
authors: Peres
authors: Boston Medical Center, Boston, Massachusetts, USA.
authors: Mary
authors: M
authors: Gaeddert
authors: Boston Medical Center, Boston, Massachusetts, USA.
authors: Sandra
authors: S
authors: Armakovitch
authors: Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA.
authors: Bareng A S
authors: BA
authors: Nonyane
authors: Foundation for Innovative New Diagnostics, Geneva, Switzerland.
authors: Claudia M
authors: CM
authors: Denkinger
authors: Division of Infectious Diseases, Center for Emerging Pathogens, Rutgers-New Jersey Medical School, Rutgers Biomedical & Health Sciences, Newark, New Jersey, USA.
authors: Padmapriya
authors: P
authors: Banada
authors: Makerere University Mycobacteriology Laboratory, Kampala, Uganda.
authors: Moses L
authors: ML
authors: Joloba
authors: Boston Medical Center, Boston, Massachusetts, USA.
authors: Jerrold
authors: J
authors: Ellner
authors: Foundation for Innovative New Diagnostics, Geneva, Switzerland.
authors: Catharina
authors: C
authors: Boehme
authors: Division of Infectious Diseases, Center for Emerging Pathogens, Rutgers-New Jersey Medical School, Rutgers Biomedical & Health Sciences, Newark, New Jersey, USA.
authors: David
authors: D
authors: Alland
authors: Johns Hopkins University School of Medicine, Baltimore, Maryland, USA dsusan1@jhmi.edu.
authors: Susan E
authors: SE
authors: Dorman
mesh_terms: D000328:Adult; D003430:Cross-Sectional Studies; D005189:False Positive Reactions; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D025202:Molecular Diagnostic Techniques / Q000379:methods*; D009169:Mycobacterium tuberculosis / Q000235:genetics / Q000302:isolation & purification*; D012680:Sensitivity and Specificity; D013183:Sputum / Q000382:microbiology; D014376:Tuberculosis / Q000175:diagnosis*