Cystatin C and Kidney Function Assessment

Introduction to Cystatin C

• The American Journal of Transplantation recommends calculating eGFRcys using the 2012 CKD-EPI cystatin C equation for accurate GFR estimation in patients with cystatin C levels, such as 1.04 mg/L 1

Diagnostic Confirmation and Risk Assessment

• The KDIGO guidelines, as reported in the Annals of Internal Medicine, recommend cystatin C measurement in adults with eGFRcr 45-59 mL/min/1.73 m² without other markers of kidney damage to confirm or refute CKD diagnosis, with a confirmed CKD diagnosis if eGFRcys is <60 mL/min/1.73 m² 3
• The American Journal of Kidney Diseases suggests that measuring urine albumin-to-creatinine ratio (ACR) on a first morning void specimen is essential for assessing albuminuria in patients with elevated cystatin C levels 4

Risk Modification Strategy

• The European Heart Journal recommends initiating or optimizing blood pressure control targeting <130/80 mmHg for cardiovascular risk reduction in patients with elevated cystatin C levels 5
• The American Journal of Transplantation notes that thyroid dysfunction, such as hypothyroidism, can increase cystatin C levels, independent of GFR, highlighting the need to check thyroid function (TSH) in patients with elevated cystatin C 1
• The American Journal of Transplantation also mentions that active smoking and high-dose corticosteroid use may affect cystatin C levels, independent of GFR 6