Table 5

PPVs and NPVs for ERI-1 (score range 0–6) with cut-off values 2, 3, 4 and 5 for different possible prevalences of endometriosis

Possible prevalences (%)ERI-1≥2ERI-1≥3ERI-1≥4ERI-1≥5
Sensitivity 76.8%
Specificity 79.7%
Sensitivity 45.2%
Specificity 92.6%
Sensitivity 24.5%
Specificity 98.0%
Sensitivity 10.3%
Specificity 100.0%
PPV (%)NPV (%)PPV (%)NPV (%)PPV (%)NPV (%)PPV (%)NPV (%)
2.07.299.411.198.820.098.529.6*98.2
1.03.799.75.899.411.099.217.2*99.1
0.51.999.93.099.75.899.69.4*99.5
0.10.4100.00.699.91.299.92.0*99.9
  • Only participants with complete data for the predictors included in ERI-1 and ERI-2 (155 cases and 148 controls) were included in the analyses.

  • *PPV for ERI-1 cut-off ≥5 was calculated using a specificity of 99.5%, not 100.0%.

  • ERI-1, Endometriosis Risk Index Variant 1; ERI-2, Endometriosis Risk Index Variant 2; NPV, negative predictive value; PPV, positive predictive value.