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Table 4 Performance parameters of magnetic bead FM following blinded re-checking of discrepant results, compared with culture on MGIT 960 and Lowenstein-Jensen medium

From: Feasibility of magnetic bead technology for concentration of mycobacteria in sputum prior to fluorescence microscopy

   Culture (MGIT + LJ)
   Positive Negative Total
Magnetic bead FM (with blinded re-checking of discrepants)
  Positive 76 12 88
  Negative 31 163 194
  Total 107 175 282
Sensitivity, %
(95% CI)
71.0%
(61.5 - 79.4)
Specificity, %
(95% CI)
93.1%
(88.3 - 96.4)
Overall accuracy, %
(95% CI)
84.8%
(80.0-88.7)
PPV, %
(95% CI)
86.4%
(77.4-92.8)
NPV, %
(95% CI)
84.0%
(80.0-88.7)
  1. CI, confidence interval
  2. PPV, positive predictive value
  3. NPV, negative predictive value
  4. ZN, Ziehl-Neelsen
  5. FM, fluorescence microscopy