Should Cystatin C Be used by itself or with other Markers to Identify and Stage the Patients with Chronic Kidney Disease

Chronic kidney disease (CKD) being asymptomatic often remains undiagnosed or is diagnosed at an advanced stage. Specific symptoms of CKD usually develop at advanced stage or may be detected by chance following routine blood and urine examination. The disease is often associated with old age, diabetes, hypertention and cardiovascular disease etc. It describes abnormal kidney function and/ or structure. Urine and blood tests are used to detect and monitor kidney disease. Currently the key markers being used are abnormal urinary albumin (>30mg/g creatinine) and a persistant reduction in estimated glomerular Alteration rate (e GFR < 60ml/min/1.73m2) for three months or more irrespective of clinical diagnosis. Another way of assessing kidney functions has been by using a combination of e GFR and albumin: creatinine ratio (ACR). Increased ACR and decreased eGFR have been shown to be associated with increased risk of CKD. Accordingly patients with CKD have been staged from Stage 1 to Stage 5. Another important aspect is that kidney functions tend to decline with age and such people with age related decline in kidney functions may not progress to kidney failure. Under such circumstances staging of CKD may not work as the prognosis for a 75 year old patient with eGFR of 55 ml/min/1.73m2 may be different than that for a 45 year old patient with same e GFR. In addition eGFR may be too narrow a basis for assessing the risk of progression of CKD. Such findings potentiated the need for fairly comparable biomarkers for early detection of less severe cases of CKD.