Understanding the Basics of Diagnostic Tests for Chronic Kidney Disease

The kidneys help filter blood, remove waste products, and regulate water and electrolyte levels.

Unfortunately, a large percentage of Americans – 15% or more – are now living with chronic kidney disease (CKD).

Diagnosis of CKD is made using two simple tests — urine and blood — that assess protein in the urine and glomerular filtration rate, an estimate of how well the kidneys filter blood.


Urinalysis is a physical, chemical, and microscopic examination of urine samples. It diagnoses certain conditions, including chronic kidney disease, uremic acidosis, and diabetes.

The test involves a collection of the patient’s urine, which is then analyzed by trained staff at the lab. The test is often ordered as part of a regular medical exam, pregnancy checkup, or to screen for various health conditions when the patient is in the hospital.

A healthy person’s urine should contain minimal toxins and excess fluid. It is so that these compounds can be released through urine after being removed by the kidneys from the bloodstream.

However, if the kidneys are not functioning correctly, the toxins and excess fluid in the body will not be removed as effectively, which can cause many problems. Detecting these problems can be challenging and often requires more than one test.

Some of the most common tests for evaluating kidney function include a blood test, a urine test, and a renal biopsy. The preliminary blood test for CKD measures the level of a waste product called creatinine in your blood. Your doctor uses this test with age, size, ethnicity, and other factors to calculate how well your kidneys can filter waste.

Along with your blood test, your doctor may recommend a urine test for CKD to help identify problems early on. A urinalysis can also measure other kidney function parameters, including your estimated glomerular filtration rate (eGFR).

Your eGFR is based on how well your kidneys work and how quickly they filter out waste products in your blood. A healthy kidney should be able to filter more than 90ml of waste per minute. If your eGFR is less than this, you may have kidney disease.

Other indicators of kidney health include the concentration of the substances in the urine and the pH levels. High concentrations of phosphate in the urine and low levels of nitrites are signs of an infection or inflammation, while large amounts of proteins in the urine indicate a problem with your kidneys.

Kidney Biopsy

Kidney biopsy is a diagnostic test used for many conditions. It can help your doctor determine the cause of your kidney disease and what treatment will be best for you. It can also help find a symptom that can help your doctor know if you have kidney failure or a new kidney problem.

A biopsy is a surgical procedure that lets your doctor take a tissue sample from your kidney. After that, the selection is sent to a lab for testing. A kidney biopsy can be done in two ways: percutaneous (a type of needle biopsy) or open (a type of surgery).

A percutaneous biopsy inserts a needle into your skin, and the provider uses ultrasound or x-ray images to locate the right kidney. The provider then injects a local anesthetic to numb the area near the kidney.

After numbing, the provider marks a spot on your skin where they will insert the needle to take a sample of your kidney. The provider then uses a small, thin needle to remove a model of the kidney.

Your doctor may have to do a few passes of the needle to get enough tissue for testing. Then, pressure is applied to the site where the biopsy needle was inserted to stop any bleeding that may occur.

It is a ubiquitous and usually painless procedure. Your provider will tell you how to care for the wound and what to expect after the biopsy. It’s crucial to adhere to the directions and leave the bandage on for at least a few days.

Resting on your side after the procedure is also helpful, so your body can heal the area where the biopsy needle was inserted. After the biopsy, you shouldn’t lift anything more than 10 pounds for at least 12 hours and shouldn’t do anything that could injure your kidneys or cause bleeding.

Kidney biopsies are significant tests to diagnose and treat kidney disease. They can change the diagnosis in about 50% of patients and change the treatment regimen in about 40%. They can be helpful in a wide range of conditions, including chronic nephrotic syndrome, systemic disease, kidney failure, unexplained AKI, and transplanted kidney dysfunction. They are considered the “gold standard” of diagnostic tests for chronic kidney disease and can help your doctor choose the proper treatment regimen.

Blood Tests

Blood tests are a common way to determine how well your kidneys work. They can also be used to monitor your condition over time.

Kidneys are fist-sized organs on either side of your backbone that filter and clean your blood, taking out waste products and making urine. When they get damaged, you may need to have a variety of tests to diagnose chronic kidney disease (CKD).

A urinalysis test is one of the most critical types of lab tests. Doctors use it to check for urinary tract infections and other problems in the bladder or kidneys. If admitted to the hospital or before surgery, you may have a urinalysis test during a regular medical checkup.

It can also be used to determine if you have diabetes or other health conditions that might cause your kidneys not to work correctly. It can help your doctor determine the best treatment plan for you, especially if you take long-term medicines that could be causing kidney damage.

Urine can be tested for many things, including color and clarity, acidity, and protein. Foaming or cloudy urine can mean you have kidney stones, a urinary tract infection, or another problem.

Other tests include blood urea nitrogen (BUN) and a glomerular filtration rate (GFR). A GFR is the most accurate measure of how well your kidneys are working, and it can tell your doctor how severe the damage to your kidneys is.

A blood glucose level is also an important test to check for diabetes. A high blood sugar level can lead to problems with your heart, kidneys, and other body parts.

A blood glucose test should be routinely performed on type 2 diabetics to ensure no eye, heart, or other organ issues are occurring. This test is usually performed twice yearly, but your healthcare provider may recommend more frequent testing depending on how well you control your diabetes.

Ultrasound Scan

Ultrasound is a noninvasive medical test that uses high-frequency sound waves to create live images of the inside of the body. It’s a painless, safe procedure that helps doctors diagnose and treat illnesses like kidney diseases.

It also monitors kidney function in patients with chronic kidney disease or other conditions. It’s often performed with other diagnostic tests, including X-rays and blood tests.

An ultrasound scan of the kidneys (also called a renal ultrasound) is a noninvasive exam that uses sound waves to produce pictures of the kidneys and bladder. It’s used to check for signs of kidney problems, such as a tumor or blockage.

A transducer device is placed on the skin and emits sound waves, which travel into the body and bounce back. These sound echoes are recorded, and a computer uses them to create an image.

The transducer is held against the patient’s skin, and a gel is applied. The gel is designed to prevent air pockets from forming between the probe and the patient’s skin.

During the exam, sound waves bounce off the kidneys and are collected by the transducer, which then transmits them to a computer to depict images of the organs. These black-and-white images can help physicians diagnose and treat kidney disorders like cysts and stones.

A kidney ultrasound is also used to assess blood flow in the kidneys. Doppler ultrasound can show whether the blood vessels are obstructed and how quickly they’re moving, indicating if they’re damaged or diseased.

This type of imaging can help detect kidney cancer and other abnormalities and provide information about the tumor’s size, shape, and location. However, it can’t see all tumors, and the accuracy of ultrasound for diagnosing kidney cancer is low.

If you want an ultrasound test, your doctor will tell you what to expect during the process. In most cases, an ultrasound can be done in just a few minutes. It’s essential to follow the doctor’s instructions, such as fasting for a few hours before the exam or drinking a lot of water before the test.

About the author: Mike

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