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Table 2 Raw data, sensitivity, specificity and positive predictive value and negative predictive value for the four different delays in pharmacy pick-ups

From: Identification of losses to follow-up in a community-based antiretroviral therapy clinic in South Africa using a computerized pharmacy tracking system

Delays of
pharmacy
pick-ups,
weeks*
a b c d Sensitivity
%(95% CI)
Specificity
%(95% CI)
PPV
% (95% CI)
NPV
% (95% CI)
≥6 85 475 0 1988 100.0 (95.8-100.0) 80.7 (79.1-82.3) 15.2 (12.2-18.2) 100.0 (99.8 -100.0)
≥12 85 109 0 2354 100.0 (95.8-100.0) 95.6 (94.7-96.4) 43.8 (36.8-50.9) 100.0 (99.8-100.0)
≥18 53 64 32 2399 62.4 (51.2-72.6) 97.4 (96.7-98.0) 45.3 (36.1-54.5) 98.7 (98.1-99.1)
≥24 40 40 45 2423 47.1 (36.1-58.2) 98.4 (97.8-98.8) 50.0 (38.8-61.2) 98.2 (97.6-98.7)
  1. *Pharmacy delays detected by iDART were compared to true LTFU status; a, true positives; b, false positives; c, false negatives; d, true negatives; PPV, positive predictive value; NPV, negative predictive value; %, percentage and CI, confidence intervals