Urinary RBP4 levels were found to be significantly increased (even >104-fold) in a plethora of human diseases, affecting kidneys in both a direct or an indirect manner, e.g., glomerulopathies, prediabetes, diabetes, renal allograft dysfunction, chronic kidney disease, preeclampsia, renal cancer, and many others [13,14,15]. Here, RBP4 is linked to chronic kidney disease.