KL and chronic kidney disease: For instant, NGAL serves as an early diagnostic tool for AKI before creatinine elevation, allowing quicker intervention.40 BTP better estimates GFR in specific patients, like those with low muscle mass.41 Similarly, Klotho and Fetuin-A offer prognostic insights into CKD progression and vascular calcification but are hindered by research inconsistencies and standardization challenge.42 Although it requires further validation.