title: Cost-effective identification of Mycobacterium tuberculosis complex using microscopic morphology and rapid tests.
abstract: BACKGROUND
  The rapid diagnosis of tuberculosis (TB) by detecting and identifying Mycobacterium tuberculosis complex (MTC) in clinical culture isolates can be achieved by a combination of rapid tests.
  
  
  OBJECTIVE
  To propose a cost-effective laboratory protocol for MTC identification.
  
  
  METHODS
  MTC (n = 278) was identified using microscopic morphology, two immunochromatographic assays (ICAs) (Tibilia™ and MeDiPro(®) M. tuberculosis Antigen Rapid Test) and the strand displacement amplification (SDA) method (ProbeTec), and the results were compared.
  
  
  RESULTS
  Microscopic morphology (cord-like) had a sensitivity of 99.3%, a specificity of 84.3%, a positive predictive value (PPV) of 88.2% and a negative predictive value (NPV) of 99.1%. The overall sensitivity/specificity of the Tibilia, MeDiPro and ProbeTec assays were respectively 98.7%/98.4%, 88.0%/85.2% and 97.4%/98.4%. The PPV/NPV for Tibilia, MeDiPro and ProbeTec were respectively 98.7%/98.4%, 87.4%/85.8% and 98.7%/96.8%. Cord-like microscopy was the least expensive method and could be used for the identification of MTC. ICA offers cost-effective screening compared to the SDA method. Tibilia performed better than MeDiPro, while its diagnostic value was similar to the SDA method.
  
  
  CONCLUSIONS
  We recommend a combination of microscopic morphology and Tibilia to further improve the sensitivity and PPV of MTC identification at lower cost.
authors.affiliation: Section of Microbiology, Department of Pathology and Laboratory Medicine, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan.
authors.forename: H-Z
authors.initials: HZ
authors.lastname: Tu
authors.affiliation: Graduate Institute of Human Resource and Knowledge Management, National Kaohsiung Normal University, Kaohsiung, Taiwan.
authors.forename: Y E
authors.initials: YE
authors.lastname: Lin
authors.affiliation: Section of Microbiology, Department of Pathology and Laboratory Medicine, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan.
authors.forename: M-R
authors.initials: MR
authors.lastname: Tseng
authors.affiliation: Section of Microbiology, Department of Pathology and Laboratory Medicine, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan.
authors.forename: T-S
authors.initials: TS
authors.lastname: Huang
authors.affiliation: Department of Medicine, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan; National Yang-Ming University, Taipei, Taiwan.
authors.forename: Y-S
authors.initials: YS
authors.lastname: Chen
mesh_terms: D002846:Chromatography, Affinity / Q000191:economics / Q000379:methods*; D003362:Cost-Benefit Analysis; D006801:Humans; D008853:Microscopy / Q000191:economics / Q000379:methods*; D009169:Mycobacterium tuberculosis / Q000302:isolation & purification*; D021141:Nucleic Acid Amplification Techniques / Q000191:economics / Q000379:methods*; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D014376:Tuberculosis / Q000175:diagnosis* / Q000382:microbiology