Creatinine 170umol/L has exceeded the normal value range and reached renal insufficiency. Therefore whether creatinine 170umol/L is serious or not is related to which of the following factors: i. If it is a transient creatinine elevation, it is not particularly serious. For example, acute glomerulonephritis, which is common in clinical practice, may have a transient increase in creatinine, but it has a tendency to heal itself, and creatinine can be reduced to normal after a period of time. If chronic renal insufficiency creatinine 170umol/L, can be further deterioration of renal function with the prolongation of time, creatinine further increase, and even develop to the uremia stage, so more serious. Secondly, it depends on what is the primary cause of renal insufficiency, renal insufficiency caused by ANCA-related vasculitis and so on, the prognosis is relatively poor, like renal insufficiency caused by amyloidosis, the prognosis is also relatively poor. If the creatinine is elevated due to chronic glomerulonephritis, the progression of the disease is relatively slow.