Tests for Chronic Kidney Disease
Reviewed by: HU Medical Review Board | Last reviewed: December 2022
Chronic kidney disease (CKD) is a condition in which your kidneys work less and less well over time. Early diagnosis is key. The sooner you know you have kidney disease, the sooner you can treat it.1
Most people have 2 kidneys, and they have a very crucial function. Throughout the day, they filter and remove excess water and waste from your blood, turning it into pee (urine). If your kidneys are not working well, water and waste build up in your body.1,2
There are several tests that doctors use to diagnose and monitor kidney disease. These include blood tests, urine tests, imaging tests, and more.1
Blood tests
The main blood test used for checking kidney function measures your glomerular filtration rate (GFR). The GFR test tells how well your kidneys are filtering your blood. It also helps your doctor determine how advanced your kidney disease is. This is known as its stage.1,3,4
Your GFR number takes into account your age, sex, and body size, as well as the levels of creatinine in your blood. Creatinine is a waste product produced by normal wear and tear of the muscles. It is usually filtered out by the kidneys. When your creatinine levels are high, your kidneys may not be effectively filtering it.3,4
Another helpful blood test is a comprehensive metabolic panel (CMP). A CMP measures 14 different substances in the blood. These measurements, or levels, provide information about how well different organs and systems in your body are working.5
Urine tests
Your pee can also tell your doctor a lot about your kidney function. There are 2 urine tests used to check kidney function. Both check for albumin in your pee. Albumin is a protein that shows up in your pee when your kidneys are not working well. Having albumin in your pee could be a sign of kidney disease.1
Your doctor may use one or both of the following urine tests to check your albumin levels:1
- Dipstick test – In this test, a strip of paper that has been chemically treated is placed into your pee sample. If the paper changes color, albumin is present.
- Urine albumin-to-creatinine ratio (UACR) – This urine test measures the ratio of albumin to creatinine in your pee.
Imaging tests
Imaging tests take pictures of the inside of your body using advanced technology. An expert in interpreting imaging scans called a radiologist performs these tests.5-8
Imaging tests can be helpful in spotting problems related to the kidneys, such as:5-9
- Fluid buildup
- Inflammation
- Tumors or lesions
- Any disruption to the urinary system
Your doctor may order one or more of the following imaging tests to get a detailed look at your kidneys:5-9
- Ultrasound – Ultrasounds use sound waves to look at your kidneys and the surrounding area.
- Kidney, ureter, and bladder (KUB) X-ray – KUB X-rays take pictures of your urinary tract, bladder, and kidneys. The ureters carry urine from your kidneys to your bladder.
- Computed tomography (CT) scan – CT scans offer more precise imaging of the kidneys than KUB X-rays. They use a combination of X-rays and computer technology.
- Intravenous pyelogram (IVP) or intravenous urogram (IVU) – This special kind of X-ray looks at the whole urinary system, including the kidneys, ureters, and bladder. During an IVP, a contrast dye is injected into a vein. The dye shows up on X-ray images, allowing a radiologist to see it as it moves through your urinary system. Dye that does not move or moves too slowly may mean there is a blockage or problem with kidney function.
Kidney biopsy
In some cases, your doctor may recommend a kidney biopsy. This is when a small tissue sample is taken from your kidney to analyze in a lab. A biopsy is only done when other tests have not provided clear answers and the cause of your kidney disease cannot be explained.10
For the biopsy procedure, your doctor gives you local anesthesia to numb the area. Then, they insert a long, thin needle through your skin and into one of your kidneys. With this needle, they remove a small tissue sample to send to a lab, where experts can study it.10
Things to consider
Some of these tests require some preparation beforehand, such as not eating or drinking (called fasting) for several hours. Talk with your care team about what you need to do to prepare for these tests and any concerns you may have. Together with a medical history and physical exam, these tests can help determine how well your kidneys are working.4
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