Evaluation of a haemozoin-based rapid diagnostic test for diagnosis of imported malaria during the phase of prevention of reestablishment in Sri Lanka

Table 2 Performance characteristics of diagnostic tests (n = 440)

	Microscopy (gold standard)/ RDT/PCR
	Positive	Negative
Gazelle
Positive	7	0
Negative	2	431
Sensitivity (95% Cl)	77.8% (40.0% to 97.2%)
Specificity (95% Cl)	100.0% (99.2% to 100.0%)
PPV(95% Cl)	100.0%
NPV(95% Cl)	99.6% (98.5% to 99.9%)
Accuracy (95% Cl)	99.6% (98.4% to 100.0%)
Odds ratio	NA
Positive likelihood ratio	NA
Negative likelihood ratio	0.222

Positive Likelihood Ratio = Sensitivity/(1-Specificity)
Negative Likelihood Ratio = (1- Sensitivity)/Specificity
DOR = (TP/FN)/(FP/TN) where DOR is Diagnostic Odds Ratio
The performance of the Gazelle was compared with the other diagnostic methods tested (i.e., microscopy, RDT and PCR). Similar results were obtained for all 3 comparisons. Specificity, sensitivity, PPV, NPV and accuracy (with 95% confidence intervals) for Gazelle as compared to microscopy, RDT and PCR are given in Table 2. Gazelle diagnosed only 7 malaria infections while all other methods detected 9 infections

ISSN: 1475-2875