Types and normal ranges of kidney function tests

Kidney function tests are basic procedures that use blood or urine to diagnose kidney abnormalities. A variety of kidney function tests are available to assess various aspects of renal health.

A kidney function test can detect sluggish waste filtering. Another test may detect protein leakage from the kidneys.

In cases where a doctor suspects a kidney disease, routine testing can help all individuals.

According to the National Kidney Foundation, 1 in 3 adults in the US is at risk for kidney disease, and many early cases show no symptoms. It’s important to detect and treat this condition early to avoid permanent damage.

In this article, you’ll learn about kidney function tests and their results.

What is it?

consulting a doctor

Kidney function tests use blood or urine to assess many elements of kidney health.

Doctors frequently request multiple tests to provide a comprehensive picture of kidney health.

The kidneys are vital to the body’s wellbeing. Their major function is to filter waste from the blood and excrete it in the urine.

Kidney disease can hinder the kidneys from filtering waste effectively, causing hazardous symptoms.

Regular testing may help detect disorders like kidney disease early on, halting its disease.

Doctors may also arrange imaging or a biopsy to learn more about the kidney.

Continue reading to learn about kidney function testing.

Urine tests

Pee tests may demand a little sample or all of a person’s urine in 24 hours.

Urinalysis

Urinalysis helps doctors uncover underlying disorders or decide which test to employ next. Urinalysis can discover unwanted particles in urine such as:

  • sugar
  • protein
  • pus
  • blood
  • bacteria

A positive test for one or more of these particles means:

The microalbuminuria or albumin-to-creatine ratio

Both tests require a little urine sample. Both aid in detecting albumin in urine.

Albumin is an important protein in the blood. Not doing your job properly if your kidneys excrete too much albumin.

30 mg/g or less urine albumin is normal. Any higher may indicate renal disease.

As a result, microalbuminuria can detect even minute levels of protein in the urine.

Even if other urine protein tests are negative, people at increased risk of renal disease may need a microalbuminuria test.

Creatine clearance

A creatine clearance test involves both blood and urine. It entails taking a 24-hour urine sample and a blood sample.

Creatine is a naturally occurring waste product in the body from muscular use.

Doctors compare creatine levels in urine to blood levels. This chart compares the amount of waste the kidneys filter out, which may indicate their general health.

Blood tests

An arm blood test requires a doctor or nurse to extract a little amount of blood from the patient. The person may need to fast or take the test early in the morning.

Serum creatine test

Serum creatine levels that are excessively high could indicate that the kidneys aren’t doing their job properly. As part of the creatine clearance test, doctors will also prescribe a serum creatine test.

Serum creatine levels exceeding 1.2 for women and 1.4 for men, according to the National Kidney Foundation, may be an early warning that the kidneys aren’t working properly. As renal disease advances, these figures may grow even higher.

This test can also be used to calculate a person’s glomerular filtration rate (GFR) to confirm a diagnosis or to order additional tests to double-check the results.

The GFR test adjusts the findings of a serum creatine test for a variety of parameters, including age, gender, and race. A GFR of 60 or higher is considered normal. A GFR of 60 or less is indicative of renal disease.

Blood urea nitrogen test

The blood urea nitrogen (BUN) test looks for urea nitrogen and other waste products in the blood.

When proteins in food break down, urea nitrogen is produced, and high amounts may indicate that the kidneys are not filtering these waste products adequately.

BUN levels typically range from 7 to 20 milligrammes per deciliter. Higher levels could indicate a kidney-related underlying condition.

However, numerous other factors, such as drugs or antibiotics, might impact BUN levels. A diet high in protein may also have an impact on levels.

To acquire a better picture of how successfully the kidney filters this waste, doctors would often compare these results to the results of a creatine test.

Imaging tests

Imaging scans may aid in the detection of any physical abnormalities to the kidneys, such as injuries or kidney stones.

Ultrasounds

To take photos, ultrasound exams use innocuous sound waves. An ultrasound may be ordered by a doctor to check for changes in the shape or position of the kidneys. An ultrasound may also be requested to screen for tumours or obstructions, such as kidney stones.

CT scans

A CT scan is a procedure that employs a sequence of X-ray images to build a 3D image of the kidneys. It could aid in the detection of any structural alterations or deformations in the kidney.

A dye injection is sometimes required for the scan, which might be problematic for people who have kidney disease.

Biopsies

Doctors may recommend a kidney biopsy in some instances. This is a procedure in which a tiny needle is inserted into the kidney to remove renal tissue. The tissue will be sent to a lab for testing by the doctor.

When doctors need to diagnose a specific disease and determine how well it might react to treatment, they may perform a biopsy. A biopsy may also be used to assess the progression of renal disease.

Results

Multiple positive test findings indicate that there is a problem with the kidneys.

Each of these tests provides doctors with a more complete view of a person’s overall kidney health. The scans can also detect renal disease signs, allowing for the ordering of additional tests.

Doctors will strive to completely identify the condition and design a treatment strategy once they have determined that there is a problem with the kidneys.

Kidney failure can be caused by a variety of underlying diseases. In order to discover the best treatment for each instance, a comprehensive diagnosis is required.

Conclusion

Renal function tests are an important element in diagnosing and treating kidney problems. Even if there are no symptoms, some people may need to be tested on a regular basis.

People at increased risk for kidney problems should get frequent kidney function testing, according to the National Institute of Diabetes and Digestive and Kidney DiseasesTrusted Source. Those with the following people are at a high risk:

Regular renal function testing can help detect kidney abnormalities early on, when the outlook is the best.

People can assist prevent the condition from progressing by sticking to a treatment plan. The best method to evaluate and manage any indicators of kidney damage or underlying issues is to work directly with a doctor.

Sources:

  • https://www.ncbi.nlm.nih.gov/books/NBK507821/
  • https://www.kidney.org/atoz/content/know-your-kidney-numbers-two-simple-tests
  • https://www.medicalnewstoday.com/articles/325397
  • https://www.kidney.org/atoz/content/kidneytests