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Table 2 Performance of the Genotype MTBDRplus assay in detecting resistance in clinical isolates of Mycobacterium tuberculosis

From: Diagnostic accuracy and usefulness of the Genotype MTBDRplus assay in diagnosing multidrug-resistant tuberculosis in Cameroon: a cross-sectional study

Gold standard: BACTEC MGIT DST 960 System(# of Mtb isolates)

Ā Ā 

RIF

INH

MDR-TB

Test assay

Ā 

Resistant

Susceptible

aResistant

Susceptible

Resistant

Susceptible

(nĀ =Ā 49)

(nĀ =Ā 176)

(nĀ =Ā 60)

(nĀ =Ā 165)

(nĀ =Ā 49)

(nĀ =Ā 176)

MTBDRplus

Resistant

48

0

55

1

46

0

Susceptible

1

176

5

164

3

176

Sensitivity (95% CI)

98 (89ā€“100)

92 (82ā€“96)

94 (83ā€“98)

Specificity (95% CI)

100 (98ā€“100)

99 (97ā€“100)

100 (98ā€“100)

PPV (95% CI)

100 (93ā€“100)

98 (91ā€“100)

100 (92ā€“100)

NPV (95% CI)

99 (97ā€“100)

97 (93ā€“99)

98 (95ā€“100)

Cohenā€™s kappa (95% CI)

0.99 (0.96ā€“1.00)

0.93 (0.88ā€“0.99)

0.96 (0.92ā€“1.00)

  1. Abbreviations: CI Confidence interval, RIF Rifampicin, INH Isoniazid, MDR-TB Multidrug resistant Tuberculosis, PPV Positive Predictive Value, NPV Negative Predictive Value
  2. aINH Resistant (nĀ =Ā 60) refers to all INH resistant isolates that is; INH and RIF drug-resistant (nĀ =Ā 49), INH mono drug-resistant (nĀ =Ā 6) and INH poly drug-resistant (nĀ =Ā 5)