Table 3

Metrics of the diagnostic performances of serum sIL7R concentrations, serum dsDNA Ab titres, serum C3 concentrations and UPC ratios for the detection of a renal BILAG A in a cohort of SLE nephritis patients

sIL7R>1042 pmol/mLdsDNA Ab titres>50 U/mLsIL7R>1042 pmol/mL and dsDNA Ab titres>50 U/mLUPC>0.5sIL7R>1042 pmol/mL and UPC>0.5serum C3<85 mg/dLsIL7R>1042 pmol/mL and serum C3<85 mg/dL
True positive1212101410139
True negative59556965714167
False positive1317371315
False negative4462637
Sensitivity (CI)—%75.0 (47.4 to 91.6)75.0 (47.4 to 91.7)62.5 (35.8 to 83.7)87.5 (60.4 to 97.8)62.5 (35.8 to 83.7)81.2 (53.7 to 95.0)56.2 (30.5 to 79.2)
Specificity (CI)—%81.9 (70.7 to 89.7)76.4 (64.6 to 85.2)95.8 (87.5 to 98.9)90.3 (80.4 to 95.7)98.6 (91.5 to 99.9)56.9 (44.8 to 68.4)93.0 (83.7 to 97.4)
Predictive positive value (CI)—%48.0 (28.3 to 68.2)41.4 (24.1 to 60.9)76.9 (46.0 to 93.8)66.7 (43.1 to 84.5)90.9 (57.1 to 99.5)29.5 (17.2 to 45.4)64.3 (35.6 to 86.0)
Predictive negative value (CI) %93.6 (83.7 to 97.9)93.2 (82.7 to 97.8)92.0 (82.8 to 96.7)97.0 (88.7 to 99.4)92.2 (83.2 to 96.8)93.2 (80.3 to 98.2)90.5 (80.9 to 95.8)
Positive likelihood ratio4.15 (2.35 to 7.32)3.18 (1.92 to 5.25)15 (4.65 to 48.4)9 (4.35 to 18.6)45 (6.2 to 327)1.89 (1.32 to 2.69)8.1 (3.13 to 20.9)
Negative likelihood ratio0.30 (0.13 to 0.71)0.33 (0.14 to 0.77)0.39 (0.21 to 0.73)0.14 (0.04 to 0.51)0.38 (0.04 to 0.18)0.33 (0.12 to 0.93)0.47 (0.27 to 0.82)
  • dsDNA, double-stranded DNA; sIL7R, soluble form of the interleukin-7 receptor; UPC, urinary protein to creatine.