What is Creatinine? High and low values | Lab results explained

A creatinine test reveals important information about your kidneys.

Creatinine is a chemical waste product of creatine, an amino acid made by the liver and stored in the liver. Creatinine is the result of normal muscle metabolism. The chemical enters your bloodstream after it’s broken down. Your kidneys remove it from your blood. The creatinine then exits the body through urination.

This test can find out whether your kidneys are working normally or to see if treatment for kidney disease is working. The creatinine in your urine can vary a lot based on diet, exercise, and hydration levels, so a spot check is not as helpful and hence one can do a 24hr volume test. For this test urine is collected numerous times during one day (waking, morning, afternoon, night) to get a good indication of how the creatinine levels fluctuate over one whole day.

If test results are abnormal, other tests will be done to make a specific diagnosis.

Lower levels:

Low levels of creatinine in the urine may point to a kidney disease, certain muscular and neuromuscular disorders, or a blockage in the urinary tract.

Low creatinine levels can be caused by:

  • A muscle disease (ex.: muscular dystrophy.)
  • A liver disease. Poor liver function interferes with creatine production, which can cause low creatinine.
  • Excess water loss. Pregnancy, excess water intake, and certain medications can cause this.

Since the breakdown of muscle tissue produces creatinine, low levels of this chemical waste often occurs in people with low muscle mass. This, however, doesn’t necessarily mean there’s a medical problem.

A reduction in muscle mass is common in older individuals, as most people lose muscle mass as they age. Low muscle mass can also result from malnutrition, or from eating a low-meat or low-protein diet.

Higher levels:

Higher levels may mean that you have kidney disease.

Possible causes of a higher creatinine level include:

  • kidney damage
  • kidney failure
  • kidney infection
  • decreased blood flow to the kidneys
  • dehydration

If you have high creatinine levels, symptoms may include:

  • nausea
  • vomiting
  • fatigue
  • changes in urination
  • high blood pressure
  • chest pains
  • muscle cramps

When creatinine begins to accumulate in the body, doctors have to run tests to check for kidney problems.


The information on is NOT intended to replace a one-on-one relationship with a qualified health care professional and is not intended as medical advice.

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