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Table 4 Sensitivity, specificity, PPV and NPV of LM 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*
LM + ve LM−ve LM−ve LM + ve % (95 % CI) % (95 % CI) % (95 % CI) % (95 % CI) (Kc)
Overall 47 78 82 2a 37.6 (29.6–46.3) 97.6 (91.7–99.7) 95.9 (86.3–98.9) 51.3 (43.2–59.2) 61.7 (0.307)
Age (years) (n = 209)
≥10 41 65 71 2 38.7 (30.0–48.2) 97.3 (90.5–99.7) 95.3 (84.5–98.7) 52.2 (43.5–60.8) 62.6 (0.329)
<10 6 13 11 0 31.6 (12.6–56.6) 100 (71.5–100) 100 (54.1–100) 45.8 (25.6–67.2) 56.7 (0.253)
Fever 48 h prior to study (n = 209)
Yes 40 3 2 2 93.0 (81.4–97.6) 50.0 (6.8–93.2) 95.2 (84.2–98.7) 40.0 (5.3–85.3) 89.4 (0.386)
No 7 75 80 0 8.5 (3.5–16.8) 100 (95.5–100) 100 (59.0–100) 51.6 (43.5–59.7) 53.7 (0.084)
History of anti-malarial drug intake 1 week prior to the survey (n = 208)
Yes 19 37 30 0 33.9 (22.9–47.0 100 (88.4–100) 100 (83.2–100) 44.8 (33.5–56.6) 57.0 (0.264)
No 28 40 52 2 41.2 (30.3–53.0) 96.3 (87.5–99) 93.3 (78.7–98.2) 56.5 (46.3–66.2) 75.6 (0.349)
  1. CI confidence interval, PCR polymerase chain reaction, LM light microscopy, 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 LM and PCR divided by the total number of cases
  2. * The agreement between LM and PCR was significant in all categories with p < 0.05
  3. aParasite densities of these two cases were 80 parasites and 400 parasites/µL