Table 1.

Specificity and sensitivity of capillary C4d staining and posttransplant FlowPRA testinga

TestSpecificity (%) (95% CI)Sensitivity (%)(95% CI)PPV (%) (95% CI)NPV (%) (95% CI)
a PPV, positive predictive value; NPV, negative predictive value; CI, confidence interval; PTC, peritubular capillaries. FlowPRA reactivity was assessed as detailed in Materials and Methods. Posttransplant flow cytometric crossmatch (FCXM) testing was defined as the standard method for the detection of alloantibody-mediated immunity. By definition, the specificity and sensitivity of a positive posttransplant FCXM result were assumed to be 100%.
C4d deposits in PTC93 (86 to 100)31 (20 to 42)87 (73 to 100)47 (33 to 61)
FlowPRA reactivity of ≥5%69 (56 to 82)60 (48 to 72)74 (63 to 86)53 (38 to 69)