Table 2

Performance parameters of ZN, Magnetic bead FM and concentrated FM compared with culture

Direct ZN

Magnetic bead-FM

Concentrated FM

Direct FM*


Sensitivity, %

(95% CI)

51.4%

(41.5 - 61.2)

65.4%

(55.6 - 74.4)

74.8%

(65.4 - 82.7)

58.9%

(49.0 - 68.3)


Specificity, %

(95% CI)

98.9%

(95.9 - 99.9)

88.6%

(82.9 - 92.9)

94.3%

(89.7 - 97.2)

99.4%

(96.9 - 100.0)


Overall accuracy, %

(95% CI)

80.9%

(75.8 - 85.3)

79.8%

(74.6 - 84.3)

86.9%

(82.4 - 90.6)

84.0%

(79.2 - 88.1)


PPV, %

(95% CI)

96.5%

(87.9 - 99.6)

77.8%

(67.8 - 85.9)

88.9%

(80.5 - 94.5)

98.4%

(91.6 - 100.0)


NPV, %

(95% CI)

76.9%

(70.8 - 82.2)

80.7%

(74.4 - 86.1)

85.9%

(80.2 - 90.5)

78.9%

(73.9 - 84.9)


* Direct FM was performed in the routine microbiology laboratory, Mulago Hospital

CI, confidence interval

PPV, positive predictive value

NPV, negative predictive value

ZN, Ziehl-Neelsen

FM, fluorescence microscopy

Albert et al. BMC Infectious Diseases 2011 11:125   doi:10.1186/1471-2334-11-125

Open Data