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Table 6 Sample 2 by 2 table for assessing diagnostic performance characteristics (sensitivity, specificity, positive predictive value, and negative predictive value) for ICD-10 code N17x

From: Validation of administrative database codes for acute kidney injury in kidney transplant recipients

  Reference standard: AKIN definition of AKI
≥2-fold increase in serum creatinine concentration from baseline <2-fold increase in serum creatinine concentration from baseline
Code N17x positive True positive (TP) False positive (FP)
Code N17x negative False negative (FN) True negative (TN)
  1. Sensitivity (Sn) = TP ÷ (TP + FN); the proportion of patients with ≥2-fold increase in serum creatinine concentration from baseline who are code N17x positive
  2. Specificity (Sp) = TN ÷ (FP + TN); the proportion of patients with <2-fold increase in serum creatinine concentration from baseline who are code N17x negative
  3. Positive predictive value (PPV) = TP ÷ (TP + FP); the proportion of patients who are code N17x positive with ≥2-fold increase in serum creatinine concentration from baseline
  4. Negative predictive value (NPV) = TN ÷ (FN + TN); the proportion of patients who are code N17x negative with <2-fold increase in serum creatinine concentration from baseline
  5. Positive likelihood ratio (LR+) = sensitivity/(1-specificity)