Table 3

Diagnostic value of the classic diagnostic parameters and detectable u-IL-16 for PLN

ParametersSensitivitySpecificityPPVNPVP value*
PLN vs other active SLE
 Positive a-dsDNA, %81.839.043.479.00.025
 Low C3, %78.471.355.887.7<0.0001
 Low C4, %91.955.048.693.6<0.0001
 u-IL-16†, %67.091.077.585.1<0.0001
PLN vs other LN classes
 Positive a-dsDNA, %81.851.466.063.30.012
 Low C3, %78.460.077.860.00.0082
 Low C4, %91.955.078.678.60.0002
 u-IL-16†, %67.083.883.366.0<0.0001
  • *P value for two-tailed Fisher’s exact test.

  • †The most optimal threshold value to calculate u-IL-16 sensitivity and specificity for PLN was determined as 15.8 pg/mL or higher, based on receiver operator characteristic curve analysis. Information on missing data is provided in the legend of tables 1 and 2.

  • a-dsDNA, anti-double-stranded DNA; LN, lupus nephritis; NPV, negative predictive value; PLN, proliferative lupus nephritis; PPV, positive predictive value; SLE, systemic lupus erythematosus; u-IL-16, urinary interleukin 16.