IL6 and bacterial urinary tract infection: Patients with minor symptoms and not receiving antibiotics had lower levels of IL-6 than patients receiving antibiotics for a suspected UTI (point estimates not given) (P < .0001).26 At a threshold of 25 ng/ml, urinary IL-6 was associated with a sensitivity of 57%, a specificity of 80%, a PPV of 52% and an NPV of 83% for differentiating treated UTI from ASB.