Should you take a kidney function test? The only way to answer this question is to identify if you are at risk for kidney function issues, often also known as chronic kidney disease (CKD).

In this article, we want to talk you through kidney function, the risk factors and causes of CKD, some of the symptoms one may expect from CKD and whether it might be time for you to take a test.

The kidneys are two bean shaped organs that are located in the upper abdominal area against the back muscles. Your kidneys sit on the left and right side of the body. Kidneys are one of the few organs that you can lose half of, and still be able to function just fine, in most causes.

30 million American adults currently have CKD and millions of Americans are currently at an increased risk of developing the condition.

Early detection, as always, is the best cure because often people who are living with kidney function issues will not experience any signs and symptoms until the condition has progressed to serious kidney disease or kidney failure. Kidney failure is defined as when one or both kidneys fail and the damage cannot be reversed.

Let's run through the top kidney function facts so you never need to worry when it comes to your kidney function.



What Is Normal Kidney Function?

Normal kidney function includes the filtering of waste products, balancing the biological water-salt ratio, regulating blood pressure, red blood cell production and regulating acid levels in the stomach.


Some kidney functions include:

Filtering Waste Products
The kidneys filter out toxins, excess salt, urea and waste products of the cells. Urea is a major waste product of the kidneys and is made by all humans. Urea is also a major component of urine.

Balancing Bodily Water-Salt Ratio
Traditionally, it has been believed that the body balances your water to salt ratio through signals to the brain to create the sensation of thirst. Once thirsty, we are compelled to drink water and kidneys work to expel excess salt from the body through urination. If it was not possible to drink water at the time of dehydration, the kidneys soak water up from the body to maintain hydration in the absence of water. It has been proven that the body regulates the salt and water balance not only by releasing excess sodium in urine, but by actively retaining or releasing water in urine. The kidneys conserve or releases water by balancing levels of sodium, potassium, and the waste product urea.

Regulating Your Blood Pressure
The kidneys require a constant healthy blood pressure to filter the blood. If blood pressure is low, the kidneys produce a protein called angiotensin and a hormone called renin. Angiotensin is a protein that causes the vessels to constrict. This in turn makes the body retain sodium and water. This acts to ensure and restore normal blood pressure.

Regulating Red Blood Cell Production
The kidneys regulate red blood cells by producing a hormone called erythropoietin (EPO). EPO is produced by the kidneys by cells that are capable of detecting tissue oxygen content. The kidneys increase the production of EPO as soon as there is a shortage of red blood cells in the tissues. Stem cells in bone marrow respond to the production of EPA by increasing the production of RBC which increases the oxygen carrying capacity of the blood.

Regulating Acid Levels
The pH scale is used to measure acidity moving from 0 (sulfuric acid) to 7 (fresh distilled water) to 14 (lye). The kidneys work as part of the body’s system that works to ensure that your body’s pH level stays balanced. In response to an increased acidity in the body, the kidneys will attempt to secrete more hydrogen and generate more bicarbonate. The kidneys are capable of balancing excess acid, however they are not capable of improving states of deficiency in the body.

What Are The Symptoms Of Acute Kidney Failure?

Chronic fatigue
Chronic fatigue is a common side effect or symptom of a number of health conditions. In the instance of kidney disease, a sufferer will feel tired all of the time because of the hindered production of erythropoietin, the hormone we spoke about earlier.

Erythropoietin is the hormone that triggers our bone marrow to begin creating red blood cells which carry oxygen. With a lower volume of red blood cells, our body and mind with tire more frequently, this condition is often referred to as anemia.

Urinating less frequently or producing a reduced volume of urine
Low urinary output may suggest that kidney disease is due to a urinary blockage, which can be caused by multiple illnesses or injuries.

If your kidney function becomes compromised, urination will be one of the tell-tale signs associated with this failure. Changes to the kidney’s structure can cause them to lose the ability to properly remove waste products from the blood.

When the body cannot eliminate urine, toxins may build up and overload the kidneys. This is one of the most common causes of kidney stones. Kidney stones occur when urine develops into hard deposits, which are made up of minerals and salts. These minerals and salts may crystallize and cause blockages. Kidney stones can offer very similar symptoms to what one would expect if one were suffering with kidney disease.

Measuring urine output is one of the simplest tests to help diagnose kidney failure.

Nausea and/or Vomiting
Feeling like you are going to be sick (nausea) and being sick (vomiting) are two common symptoms of kidney disease. There are two primary reasons for these symptoms including, A) the buildup of toxins and waste in the body can lead to infections, stomach issues and constipation which can make you feel nauseous, and B) the medication you are taking to combat the side effects of kidney disease may induce vomiting or nausea.

Shortness of breath
As mentioned earlier, often those who are living with kidney disease will face chronic fatigue. You might have been able to run around before you develop this condition, but now everything might feel like a little bit more of an effort and this might manifest in a shortness of breath.

Secondly, often if you acquire kidney disease, you might be experiencing fluid retention, this can reach the lungs, offering a sensation of a shortness or lack of breath.

This is sometimes also referred to as pulmonary edema.

In advanced and serious cases of kidney disease, an accumulation of toxins may lead to seizures.

This is may be compounded by complications such as sepsis, hemorrhage, advanced hypertension, pH and hydroelectrolytic disturbances.

Fluid retention, swelling in the legs, ankles, and feet
Kidney disease can lead to fluid retention, foot and ankle swelling. This is sometimes referred to as edema. When the kidneys are not functioning, it can lead to a fluid build-up in the body which more often than not will be visible in the legs, ankles, feet or hands.

Irregular heartbeat

In a meta-analysis of three studies that looked at almost 17,000 patients, it was proven that those who have kidney disease are more likely to have an irregular heart beat, this is thought to be connected to the fact that kidneys regulate blood pressure.

Chest pain
High blood pressure or hypertension is a common cause of kidney disease and other complications such as heart attacks and strokes.

If you live with kidney disease, you are more likely to be diagnosed with heart disease. Kidney disease often doesn’t have any symptoms until the condition is at a stage where it is likely to cause more problems, or you have developed another condition, such as heart disease, therefore one of the symptoms of kidney disease may be chest pain.


What Are The Causes Of Acute Kidney Disease?

According to the Mayo Clinic, diabetes and high blood pressure are the most common causes of kidney disease.

The third leading cause of end stage kidney disease in the U.S. is glomerulonephritis, a disease that damages the kidneys' filtering units, called the glomeruli. In many cases, the cause of this disease is not known, but some cases may be inherited and others may be triggered by an infection.

Some of the other diseases that may affect the kidneys include infections, kidney stones and inherited diseases such as polycystic kidney disease.

Drug abuse, injury and family history may also play a role in your likelihood of living with kidney disease.

Let's have a look at how diabetes and high blood pressure can often lead to kidney disease.

1. Type one and type two diabetes

Diabetes is the leading cause of kidney disease in the United States.

30% of patients with type one diabetes and 10-40% of those with type two diabetes will eventually suffer from kidney disease.

We have spoken about diabetes before and the effects that it may have on other aspects of your health. Diabetes is a condition in which the body is unable to make a sufficient volume of insulin or cannot use insulin properly and therefore the body struggles to regulate blood sugar.

When people are living with diabetes, the blood vessels of the kidneys may become damaged which can hinder your kidneys' ability to filter toxins and remove waste products from the blood. In this instance, the body may retain more water and salt than it should, the tell-tale signs of this symptom often include weight gain and ankle swelling. It is also common to have protein in your urine in these instances.

2. High blood pressure (hypertension)

High blood pressure is the second leading cause of kidney disease in the United States.

Blood pressure is defined as the force of blood pushing against blood vessel walls as the heart pumps out blood. High blood pressure, which is also known as hypertension refers to a higher level of pressure exerted by pumping blood as it moves through the blood vessels. Factors that might lead to higher blood pressure include arteries becoming narrow, stiff or clogged or a higher volume of waste products in the blood.

High blood pressure may play a role in kidney disease as blood vessels in the kidneys and around the body may become damaged. When blood vessels become damaged, the kidneys' ability to filter out toxins and byproducts may become more difficult. This build-up can cause higher blood pressure and thus becomes a dangerous cycle.

Should You Take A Kidney Function Test?


You should consider taking a Kidney Function Test if any of the below are applicable to you.

  • You suffer from high blood pressure
  • You suffer from diabetes
  • You have suffered an acute injury
  • You have persistent urinary tract infections
  • You have a kidney disease or a family history of one
  • You have kidney stones or a family history of them
  • You have a high protein diet
  • You have been taking performance enhancing drugs

The first six risk factors on this list might seem self explanatory, but how does a high protein diet or performance enhancing drugs come into this?

Well, researchers have shown that a high protein diet may worsen kidney function in people who already live with kidney disease as the body has trouble eliminating all of the waste products of protein metabolism.

When it comes to performance enhancing drugs, new findings indicate that the habitual use of steroids has serious harmful effects on the kidneys that were not previously recognized.

It is believed that drastic increases in muscle mass require the kidneys to increase their filtration rate, placing harmful levels of stress on these organs. It's also likely that steroids have direct toxic effects on the kidneys.

So when it comes to nutrition and supplementation, always bear your kidneys in mind.

The LetsGetChecked Kidney Function Test measures urea, creatinine and eGFR (estimated glomerular filtration rate) to accurately measure kidney function.

Let's take a quick look at what these biomarkers mean when it comes to measuring your kidney function.

Urea is a waste product formed from the breakdown of proteins. Urea is expelled from the body in the form of your urine. A high level of urea ('uremia') indicates that the kidneys may not function optimally, filter a sufficient level of toxins from the body, or that you are dehydrated.

Creatinine is a waste product that comes from normal wear and tear in the muscles. There is usually a constant and steady stream of creatinine in the blood.
Creatinine is a waste product made by your muscles and dietary protein. Creatinine passes into the bloodstream and is usually passed out in urine. A high blood level of creatinine indicates poor kidney function or the development of kidney disease. High creatine in the blood indicates a poor filtration rate by the kidneys.

eGFR (estimated glomerular filtration rate)
eGFR is one of the most accurate ways of measuring kidney function. eGFR (estimated glomerular filtration rate) is a calculation which determines how well your kidneys are filtering blood by measuring the level of creatine in the blood and using this number to calculate a number that reflects how well your kidneys are functioning.

Are you thinking about taking a kidney function test? If you are concerned about symptoms that you are experiencing or you would like to learn more about taking a kidney function test, you can reach out to us, or browse our tests at

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