Chronic kidney disease is identified by a blood test for creatinine.Higher levels of creatinine indicate a falling glomerular filtration rate and as a result a decreased capability of the kidneys to excrete waste products.Creatinine levels may be normal in the early stages of CKD,and the condition is discovered if urinalysis(testing of a urine sample)shows that the kidney is allowing the loss of protein or red blood cells in to the urine.To fully investigate the underlying cause of kidney damage.Various forms of medical imaging blood of chronic kidney disease in five stages,with stage 1 being the mildest and usually causing fewtests and often renal biopsy(removing small sample of kidney tissue)are employed to find out if there is a reversible cause for the kidney malfunction.
Recent professional guidelines classify the severity  symptoms and stage 5 being a severe illness with poor life expectancy if untreated.Stage 5 CKD is also called established chronic kidney disease.