Renal injury can lead to acute (AKD) or chronic kidney disease (CKD). The presence, progress and distinction between AKD and CKD can be determined by monitoring serum creatinine and BUN values. Prerenal kidney failure is the most common form of AKD. AKD can be irreversible or, alternatively, can lead to a slow recovery of kidney function. Symptoms and signs of CKD often develop slowly and depend on the percentage of functional nephrons. Individuals can remain asymptomatic until AKD is far advanced. Uremia develops during the final stage of CKD. The development of signs and symptoms of uremia correlates well with BUN values.