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Table 3 Sensitivity, specificity, PPV and NPV of PfHRP-2/pLDH RDT for detecting Plasmodium falciparum against nested PCR as a reference method

From: Field evaluation of a PfHRP-2/pLDH rapid diagnostic test and light microscopy for diagnosis and screening of falciparum malaria during the peak seasonal transmission in an endemic area in Yemen

  PCR + ve PCR + ve PCR−ve PCR−ve Sensitivity Specificity PPV NPV % Agreement*
RDT + ve RDT−ve RDT−ve RDT + ve % (95 % CI) % (95 % CI) % (95 % CI) % (95 % CI) (Kc)
Overall 119 5 47 37 96.0 (90.9–98.3) 56.0 (44.7–66.8) 76.3 (69.0–82.3) 90.4 (78.8–96.8) 79.8 (0.553)
Age (years) (n = 208)
 ≥10 100 5 41 32 95.2 (89.3–97.9) 56.2 (44.1–67.8) 75.8 (67.8–82.3) 89.1 (76.4–96.4) 79.2 (0.545)
 <10 19 0 6 5 100 (82.4–100) 54.6 (23.4–83.3) 79.2 (57.9–92.9) 100 (54.1–100) 83.3 (0.603)
Fever 48 h prior to survey (n = 208)
 Yes 42 0 2 2a 100 (92.3–100) 50.0 (6.8–93.2) 95.5 (84.9–98.7) 100 (15.8–100) 95.3 (0.646)
 No 77 5 45 35 93.9 (86.3–98.0) 56.3 (44.7–67.3) 68.8 (59.3–77.2) 90.0 (78.2–96.7) 75.3 (0.504)
History of anti-malarial drug intake 1 week prior to the survey (n = 207)
 Yes 52 2 9 21 96.3 (87.5–99.0) 30 (14.7–49.4) 71.2 (60.0–80.3) 81.8 (48.2–97.7) 72.6 (0.306)
 No 66 3 38 16 95.7 (88.0–98.5) 70.4 (57.2–80.9) 80.5 (70.6–87.6) 92.7 (80.6–97.5) 84.6 (0.678)
  1. CI confidence interval, PfHRP-2 P. falciparum histidine-rich protein-2, pLDH Plasmodium lactate dehydrogenase, RDT rapid diagnostic test, PCR polymerase chain reaction, PPV positive predictive value, NPV negative predictive value, Kc Cohen’s kappa coefficient;  % agreement was calculated by summation of the number of positives and negatives by both RDT and PCR divided by the total number of cases
  2. * The agreement between RDT and PCR was significant for all categories with p < 0.001
  3. aParasite densities of these two cases were 80 parasites and 400 parasites/µL