The diagnosis of chronic kidney disease is based on the measurement of eGFR and albuminuria, often through the albumin-to-creatinine ratio (ACR). The KDIGO guidelines recommend an eGFR of less than 60 mL/min/1.73 m² persisting for three months or more as the diagnostic criterion for CKD. Albuminuria is categorized as A1 (normal to mildly increased), A2 (moderately increased), and A3 (severely increased). The combination of eGFR and albuminuria stages allows for more precise risk stratification and prognosis.
Imaging studies, such as renal ultrasound, can identify structural abnormalities like hydronephrosis or polycystic kidney disease. In some cases, a kidney biopsy may be indicated to determine the exact cause of CKD, especially when autoimmune diseases or glomerulonephritis are suspected.
Newer biomarkers, such as neutrophil gelatinase-associated lipocalin (NGAL), kidney injury molecule-1 (KIM-1), and cystatin C, are being explored for earlier detection of CKD progression. These markers may offer better sensitivity in detecting early tubular injury before significant changes in serum creatinine are apparent.
