What Level of Creatinine Is Dangerous? Creatinine is a waste product in the blood that reflects how well your kidneys are working. Normal creatinine levels usually range from 0.6 to 1.3 mg/dL in adults. A creatinine level above 1.5 mg/dL may indicate early kidney problems, while levels above 2.0 mg/dL are considered more serious and suggest significant kidney dysfunction. Very high levels can be dangerous and require immediate medical evaluation.