Serwin NM, et al. - Researchers applied two parameters, ie, fractional excretion and serum-to-urine renalase ratio, to estimate the balance between serum and urine renalase [a flavoprotein that plays a protective role in chronic kidney disease (CKD) and cardiovascular diseases] in healthy people and CKD patients. This study was done with 28 healthy volunteers and 62 patients with CKD in stages I to IV. Findings revealed significantly and approximately 6.5-fold higher serum-to-urine ratio among CKD patients, and the estimated fractional excretion of renalase was 3-fold, but not significantly lower in CKD patients. Both serum and urine levels of renalase were not associated with the glomerular filtration rate and not related to blood pressure.