Skip to main content

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

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

  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
  1. Positive Likelihood Ratio = Sensitivity/(1-Specificity)
  2. Negative Likelihood Ratio = (1- Sensitivity)/Specificity
  3. DOR = (TP/FN)/(FP/TN) where DOR is Diagnostic Odds Ratio
  4. 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