Kidney tests are important because kidney disease often has no symptoms until your kidneys are badly damaged. So, the only way to know how well your kidneys are working is to get tested. This is especially important for people who have diabetes, high blood pressure, or a family history of kidney disease.
Ask your doctor about these tests to check your kidneys. Kidney damage usually cannot be fixed. But if you find and treat kidney disease early, you may be able to keep it from getting worse.
Blood test: eGFR
The way doctors measure how well your kidneys filter waste from your blood is by the estimated glomerular filtration rate, or eGFR. Your eGFR is a number based on your blood test for creatinine, a waste product in your blood. The stages of kidney disease are based on the eGFR number. Learn more about the eGFR test.
|Stage 1||Stage 2||Stage 3||Stage 4||Stage 5|
eGFR in normal range (greater than 90) with other signs of kidney damage, like protein in urine or physical damage to the kidneys
eGFR in normal range (60-89) with other signs of kidney damage, like protein in urine or physical damage to the kidneys
eGFR 30-59, moderate kidney damage
eGFR 15-29, severe kidney damage
eGFR less than 15, the kidneys are close to failure or have already failed
When your kidneys are damaged, they may let protein leak into your urine. This can be one of the earliest signs of kidney disease. To check for protein in your urine, your doctor may ask you to take a urine test. Learn more about the two types of urine tests your doctor may use.
One way your doctor can see if your kidneys are damaged is to do a kidney biopsy. A kidney biopsy is a procedure where your doctors take a very small piece of your kidneys to look at it closely under a microscope. Learn why you may need a kidney biopsy.
Blood urea nitrogen (BUN) test
Your blood urea nitrogen (BUN) level is based on a blood test that measures the amount of urea nitrogen in your blood. Urea nitrogen is a waste product that your body makes after it breaks down protein. Learn about a blood urea nitrogen (BUN) test.
One way your doctor can look at your kidneys is by doing a kidney ultrasound. A kidney ultrasound (also called a renal ultrasound) is a safe and painless test that uses sound waves to make images of your kidneys. Learn about a kidney ultrasound.
Serum creatinine test
Your serum creatinine level is based on a blood test that measures the amount of creatinine in your blood. It tells how well your kidneys are working. When your kidneys are not working well, your serum creatinine level goes up. Learn about a serum creatinine test.