In the present study, a novel assay system for measuring %S2,3PSA with a μTAS system discriminated patients with PCa from patients with BPH with 72.0% specificity at 80.0% sensitivity with a α2,3-sialic acid percentage cut-off of 42.20%, as indicated by an AUC of 0.8340 which was significantly higher than that for conventional PSA testing (0.5062, p < 0.0001 Figure 6e). Here, KLK3 is linked to benign prostatic hyperplasia.