Elderly persons, on the other hand, may have less creatinine in
than the norm. Infants have normal levels
of about 0.2 or more, depending on their muscle development. In people with malnutrition, severe weight loss, and long standing illnesses the muscle mass tends to diminish over time and, therefore, their creatinine level may be lower than expected for their age"
An abnormally high value can idicate a kidney disorder.