Creatinine is a form of chemical waste that our bodies produce when we eat meat but mostly due to muscle metabolism. The creatinine blood test measures the level of creatinine in the blood. This test is done to see how well your kidneys work.

If the kidneys are healthy, they are able to filter creatinine as well as other wastes out of the blood, sending them out of your body via urine. When the kidneys aren’t healthy, however, creatinine can accumulate in the bloodstream. Because of this, creatinine tests measure the amount of creatinine in urine (for a creatinine urine test) or blood (in a serum creatinine test) and use this information to determine whether the kidneys are functioning normally.

Normal range of creatinine

Women usually have lower results on the serum creatinine test because they have a lower muscle mass in their bodies. The average range for women is between 0.6 and 1.1 mg/dL and for men it increases to between 0.7 and 1.3 mg/dL. As with the urine creatinine test, the average results can vary depending on the lab and their specific tests and procedures.

Indication of abnormal creatinine levels

If you have abnormal results on your serum creatinine test, it can indicate many possibilities, some serious and others minor.

Levels that are too high can be due to urinary tract obstruction, rhabdomyolysis, and reduced blood flow to the kidneys, pyelonephritis, pre-eclampsia, muscular dystrophy, kidney failure, glomerulonephritis, eclampsia, diabetic nephropathy, dehydration or acute tubular necrosis.

Lower than normal level may be due to conditions involving the muscles and the nerves that control them or muscle problems, such as late stage muscle loss (muscular dystrophy). There are many other conditions for which the test may be ordered, such as high blood pressure, diabetes or medication overdose.