title: A performance evaluation of MTBDRplus version 2 for the diagnosis of multidrug-resistant tuberculosis.
abstract: OBJECTIVE
  To evaluate the performance of a recently updated rapid molecular diagnostic test, GenoType® MTBDRplus version 2, designed to detect drug resistance in both acid-fast bacilli (AFB) smear-negative and -positive specimens.
  
  
  METHODS
  Sputum samples from 1128 patients at risk for multidrug-resistant tuberculosis (MDR-TB) were tested using MTBDRplus v2 and compared with reference standard MGIT™ 960™ drug susceptibility testing. The relationship of participant human immunodeficiency virus (HIV) status, diabetic status, previous treatment, and smear gradation to the likelihood of obtaining an interpretable result was assessed using logistic regression.
  
  
  RESULTS
  The sensitivity and specificity of MTBDRplus v2 for detecting MDR-TB, when compared to a reference standard, were respectively 96.0% (95%CI 93.5-97.6) and 99.2% (95%CI 97.0-99.9) in AFB smear-positive specimens and 82.8% (95%CI 63.5-93.5) and 98.3% (95%CI 89.9-99.9) in AFB smear-negative specimens. A dose-response relationship was observed between the proportion of interpretable test results and AFB smear bacterial load after adjusting for age, sex, body mass index, HIV status, previous treatment and diabetic status.
  
  
  CONCLUSIONS
  While MTBDRplus v2 performs well among both AFB smear-positive and -negative specimens, smear gradation appears to influence both the probability of obtaining an interpretable result and test sensitivity, indicating a significant association between bacillary load and test performance.
authors.affiliation: University of California, San Diego, California, USA.
authors.forename: M
authors.initials: M
authors.lastname: Seifert
authors.affiliation: Hinduja National Hospital, Mumbai, India.
authors.forename: K
authors.initials: K
authors.lastname: Ajbani
authors.affiliation: University of California, San Diego, California, USA.
authors.forename: S B
authors.initials: SB
authors.lastname: Georghiou
authors.affiliation: University of Arkansas, Fayetteville, Arkansas, USA.
authors.forename: D
authors.initials: D
authors.lastname: Catanzaro
authors.affiliation: Hinduja National Hospital, Mumbai, India.
authors.forename: C
authors.initials: C
authors.lastname: Rodrigues
authors.affiliation: Institute of Phthisiopneumology, Chisinau, Moldova.
authors.forename: V
authors.initials: V
authors.lastname: Crudu
authors.affiliation: Stellenbosch University, Cape Town, South Africa.
authors.forename: T C
authors.initials: TC
authors.lastname: Victor
authors.affiliation: University of California, San Diego, California, USA.
authors.forename: R S
authors.initials: RS
authors.lastname: Garfein
authors.affiliation: University of California, San Diego, California, USA.
authors.forename: A
authors.initials: A
authors.lastname: Catanzaro
authors.affiliation: University of California, San Diego, California, USA.
authors.forename: T C
authors.initials: TC
authors.lastname: Rodwell
mesh_terms: D000328:Adult; D058491:Bacterial Load; D001431:Bacteriological Techniques / Q000592:standards; D002138:Calibration; D004269:DNA, Bacterial / Q000235:genetics* / Q000302:isolation & purification; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics*; D005260:Female; D006801:Humans; D008168:Lung / Q000382:microbiology*; D008297:Male; D008875:Middle Aged; D025202:Molecular Diagnostic Techniques / Q000592:standards; D009169:Mycobacterium tuberculosis / Q000235:genetics* / Q000302:isolation & purification; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012015:Reference Standards; D015203:Reproducibility of Results; D013183:Sputum / Q000382:microbiology; D018088:Tuberculosis, Multidrug-Resistant / Q000175:diagnosis* / Q000382:microbiology; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis* / Q000382:microbiology; D055815:Young Adult
chemical_list: D004269:DNA, Bacterial