What Is Creatinine?

Learning that you have kidney disease can come with a lot of questions. And it can often feel like you’re learning a whole new language as you talk with your doctor. One term you may have discussed with your doctor is “creatinine.” It is pronounced kree· a· tuh· neen. It can be confusing to learn new medical terms, but understanding them is an important step in taking charge of your health.

What is creatinine?

Creatinine is a waste product created by your muscles. The more muscle you have, the more creatinine your body produces. This waste product is normally filtered out of your blood by your kidneys and eliminated through urine.

Creatinine Levels and Kidney Function

Healthy kidneys can filter out creatinine with no issues. However, when there is kidney damage, such as with kidney disease, the kidneys cannot work at their full capacity and may not be able to filter creatinine as well. This can lead to a buildup of creatinine in the blood. Doctors can use creatinine tests to see how well your kidneys work and help detect any kidney problems.

Watch the video below to learn more about how creatinine levels and kidney function are related.

Creatinine Tests

There are two main tests that measure creatinine.

  • Serum Creatinine: This blood test measures the amount of creatinine in your bloodstream. Your serum creatinine is used to get your glomerular filtration rate (GFR), a measurement of kidney function. If you know your serum creatinine level, you can determine the stage of chronic kidney disease (CKD) using the DaVita GFR Calculator. It’s best to talk with your doctor, who can interpret your test results and explain what this means for your kidney health.
  • Creatinine Clearance (Ccr or CrCl): This requires both a urine test and a blood test. It is done over 24 hours and involves collecting all your urine to see how much creatinine your body removes.

What are normal creatinine levels?

Normal creatinine levels are different for men and women due to differences in muscle mass. Generally, for adults:

  • Men: 0.6 to 1.2 milligrams per deciliter (mg/dL)
  • Women: 0.5 to 1.1 mg/dL

When to Worry About Creatinine Levels

You might not feel any symptoms as your creatinine levels rise, but symptoms may also come gradually. If you’ve experienced a loss of appetite, nausea and vomiting, itching, weakness or flu-like symptoms, these symptoms might be due to high levels of creatinine and other waste buildup.

While high creatinine levels can be a sign of kidney disease, other factors can also affect these levels, such as:

  • Body size
  • Activity level
  • Medicines

Talk with your doctor about what a healthy creatinine level is for you, and what you can do to help keep your levels in check and manage your kidney health.

This article is for informational purposes only and is not a substitute for medical advice or treatment. Consult your physician regarding your specific diagnosis, treatment, diet and health questions.