Creatine is a substance that is used by the body to create energy from muscle.  Creatinine is created during the metabolism of creatine and is a waste product that is eliminated through the kidneys in the urine.  Because of the way creatinine is produced in the body, more will be produced with the more muscle mass a person has.

In addition to ordering the creatinine test in a general examination, doctors may order the test if a patient complains of:
•    Fatigue
•    Confusion
•    Trouble concentrating
•    Edema (fluid build-up causing swelling)
•    Shortness of breath


A milligram (mg) is one-thousandth of a gram.  A deciliter (dl) is one-tenth of a liter.
Although your doctor will modify the acceptable ranges based upon your size and muscle mass, the acceptable range for most men is between .7 milligrams per deciliter and 1.3 milligrams per deciliter.
Because they generally have less muscle mass than men, an acceptable range for most women is between 0.6 milligrams per deciliter and 1.1 milligrams per deciliter.


Creatinine levels that are higher than the acceptable range can indicate:
•    Kidney problems
•    Urinary tract problems
•    Dehydration


Creatinine levels lower than the acceptable range can indicate:
•    The late stages of muscular dystrophy
•    Myasthenia gravis (weakness of muscles)
Because the muscle mass in the body is relatively constant from day to day, the creatinine production normally remains essentially unchanged on a daily basis.


If there is a possible problem shown by the creatinine blood test, many doctors order the collection of urine samples over a 24 hour period.