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Table 3 Operating characteristics of the coding algorithms according to diagnostic coding system (ICD-9-CM vs. ICD-10) *

From: Validation of ICD-9-CM/ICD-10 coding algorithms for the identification of patients with acetaminophen overdose and hepatotoxicity using administrative data

Outcome/Coding System Sensitivity (95% CI) Specificity (95% CI) PPV (95% CI) NPV (95% CI) C-statistic (95% CI)
Acetaminophen overdose      
   ICD-9-CM 91% (83–96%) (81/89) 81% (61–93%) (21/26) 94% (87–98%) (81/86) 72% (53–87%) (21/29) 0.86 (0.78–0.94)
   ICD-10 88% (77–95%) (44/50) 88% (62–98%) (14/16) 96% (85–99%) (44/46) 70% (46–88%) (14/20) 0.88 (0.78–0.97)
Hepatotoxicity      
   ICD-9-CM 97% (86–100%) (36/37) 80% (66–90%) (39/49) 78% (64–89%) (36/46) 98% (87–100%) (39/40) 0.88 (0.82–0.95)
   ICD-10 86% (65–97%) (19/22) 96% (79–100%) (23/24) 95% (75–100%) (19/20) 88% (70–98%) (23/26) 0.91 (0.83–0.99)
Acute liver failure      
   ICD-9-CM 85% (55–98%) (11/13) 85% (75–92%) (62/73) 50% (28–72%) (11/22) 97% (89–100%) (62/64) 0.85 (0.74–0.96)
   ICD-10 100% (N/A) (9/9) 86% (71–95%) (32/37) 64% (35–87%) (9/14) 100% (NA) (32/32) 0.93 (0.88–0.99)
  1. * None of the comparisons between the ICD-9-CM and ICD-10 coding systems are statistically significant (P > 0.05 for all).
  2. CI, confidence interval; NPV, negative predictive value; NA, not applicable; PPV, positive predictive value.