What is creatinine?
Creatinine is a chemical waste molecule that is generated from muscle
metabolism. Creatinine is produced from creatine, a molecule of major
importance for energy production in muscles. Approximately 2% of the body's
creatine is converted to creatinine every day. Creatinine is transported
through the bloodstream to the kidneys. The kidneys filter out most of the
creatinine and dispose of it in the urine.Why is it important to
check blood creatinine levels?
The kidneys maintain the blood creatinine in a normal range. Creatinine has
been found to be a fairly reliable indicator of kidney function. As the
kidneys
become impaired the creatinine level in the blood will rise. Abnormally high
levels of creatinine thus warn of possible malfunction or failure of the
kidneys, sometimes even before a patient reports any symptoms. It is for
this reason that standard blood and urine tests routinely check the amount
of creatinine in the blood.
What are "normal" blood creatinine levels?
Normal levels of creatinine in the blood are approximately 0.6 to 1.2
milligrams (mg) per deciliter (dl) in adult males and 0.5 to 1.1 milligrams
per deciliter in adult females. (In the metric system, a milligram is a unit
of weight equal to one-thousandth of a gram, and a deciliter is a unit of
volume equal to one-tenth of a liter.)
Muscular young or middle-aged adults may have more creatinine in their
blood than the norm for the general population. Elderly persons, on the
other hand,
may have less creatinine in their blood than the norm. Infants have normal
levels of about 0.2 or more, depending on their muscle development. A person
with
only one kidney may have a normal level of about 1.8 or 1.9. Creatinine
levels that reach 2.0 or more in babies and 10.0 or more in adults may
indicate the
need for a dialysis machine to remove wastes from the blood. Certain drugs
can sometimes cause abnormally elevated creatinine levels. | 
