A blood creatinine of 305 μmol/L is generally more serious. Creatinine is a metabolite in the body, mainly related to the individual’s muscle content, and its elimination is mainly through glomerular filtration, and then excreted with urine, so in some cases, creatinine value can reflect the health of the kidneys. Causes of elevated blood creatinine can be seen in gastrointestinal bleeding, heart failure, urinary tract obstruction, glomerulonephritis, etc., and need to be treated for specific causes. A blood creatinine of 305 μmol/L indicates that the kidneys are in the stage of damage, and if not actively treated, it may progressively aggravate and eventually develop into uremia, which is life-threatening. Patients with elevated blood creatinine are advised to go to regular hospitals for timely examination to clarify the cause of elevated creatinine and follow the doctor’s instructions for standardized treatment.