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Table 3 Malaria microscopy diagnostic performance in malaria low-transmission areas in Kenya, June–December 2013

From: Evaluation of a laboratory quality assurance pilot programme for malaria diagnostics in low-transmission areas of Kenya, 2013

  Health-facility laboratory personnel Quality assurance officers
Visit 2 Visit 3 Visit 4 Visit 2 Visit 3 Visit 4
Total slides collected 709   408   509   709   408   509  
Slides read by reference laboratory 675 95% 333 82% 509 100% 675 95% 333 82% 509 100%
Reference laboratory Positive Negative Positive Negative Positive Negative Positive Negative Positive Negative Positive Negative
 Positive 48 2 8 1 8 7 48 2 8 1 9 6
 Negative 75 550 7 317 9 485 44 581 2 322 7 487
Column total 123 552 15 318 17 492 92 583 10 323 16 493
  Health-facility laboratory personnel Quality assurance officers
  95% CI   95% CI   95% CI   95% CI   95% CI   95% CI
Sensitivity 96% 86–100% 89% 52–100% 53% 27–79% 96% 86–100% 89% 52–100% 60% 32–84%
Specificity 88% 85–90% 98% 96–99% 98% 97–99% 93% 91–95% 99% 98–100% 99% 97–99%
PPV 39% 30–48% 53% 27–79% 47% 23–72% 52% 42–63% 80% 44–97% 56% 30–80%
NPV 99% 99–100% 99% 98–100% 98% 97–99% 99% 99–100% 99% 98–100% 99% 97–100%
Kappa value 0.50 0.41–0.59 0.66 0.43–0.88 0.48 0.27–0.70 0.64 0.55–0.74 0.84 0.66–1.00 0.57 0.36–0.78
  1. Italic denotes statistically significant improvement from visit 2 to visit 4
  2. CI confidence interval, PPV positive predictive value, NPV negative predictive value