You are viewing the site in preview mode
Skip to main content

Scrub typhus positive determined by definition in Table 2


Parameters

Number or percentage of positives


ELISA results

IgG

IgM

True positive (TP)

81

70

True negative (TN)

141

150

False positive (FP)

21

12

False negative (FN)

5

16

Sensitivity

94.2

81.4

Specificity

87.0

92.6

Positive predict value (PPV)

79.4

85.4

Negative predict value (NPV)

96.6

90.4

Accuracy

89.5

88.7

Likelihood ratio positive (LR+)

7.27

11.0

Likelihood ratio negative (LR)

0.07

0.20


^{a}Table shows number of samples for true positive, true negative, false positive and false negative. Sensitivity, specificity, PPV, and NPV are shown as percentage. The likelihood ratio was determined by using the following formulas: LR+ = sensitivity/ (1 – specificity), LR = (1sensitivity)/specificity. Samples are considered ELISA positive if the OD values are greater than or equal to 0.816 for IgG or 0.320 for IgM