Kidney Function Tests


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  1. Water Retention Panel: Aldosterone/Plasma Renin Activity Ratio, LC/MS/MS

    Renin, also known as angiotensinogenase, is an enzyme that the kidneys produce to regulate aldosterone production. It’s also essential in the renin–angiotensin aldosterone system (RAAS) which maintains your body’s fluid balance and blood pressure. Aldosterone is the primary of several endogenous members of the class of mineralocorticoids in humans. Aldosterone tends to promote sodium and water retention, and lower plasma postasium concentrations.

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  2. Renal Kidney Function Panel Comprehensive

    This panel includes blood and urine tests commonly used by physicians to determine kidney dysfunction: Urinalysis, Comprehensive Metabolic Panel (CMP), Cystatin C and eGFR.

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  3. Urinalysis, Complete, with Reflex to Culture

    Urinalysis with reflex to culture testing is done when the first urinalysis results are not normal or when doctors think the person might have a urinary tract infection, kidney disease, or another problem with their urinary tract. Several conditions may necessitate urinalysis with reflex testing. Urinary tract infections (UTIs) are a common reason for reflex testing, as it helps healthcare providers identify the specific bacteria causing the infection and determine the most effective antibiotic treatment. Kidney diseases, such as glomerulonephritis or renal tubular acidosis, may also require reflex testing for accurate diagnosis and management. Conditions like hematuria (blood in urine) or proteinuria (protein in urine) warrant further investigation, as they may indicate underlying kidney disease or urinary tract neoplasms. Pregnant women may undergo reflex testing to monitor for gestational diabetes and preeclampsia. NOTE: You need to visit the lab near you to submit two separate specimens in containers provided by the lab:
    1) 10 mL urine submitted in urinalysis transport tube (yellow-top, blue fill line, preservative tube)
    2) 4 mL (fill to minimum line printed on tube; unpreserved for cultures) urine in urine culture tube (gray-top) or UriSponge™ transport

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  4. CMP - Comprehensive Metabolic Panel

    Includes liver and kidney function, glucose and electrolytes

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  5. Cystatin C test with EGFR

    The cystatin C test (which also includes estimated creatinine clearance eGFR) can be done along with the creatinine or creatinine clearance test in cases where those tests aren’t appropriate, such as patients taking creatine supplements for bodybuilding. These supplements can increase creatinine and decrease creatinine clearance, which can alarm doctors who fear kidney dysfunction.  This creatinine increase is not clinically relevant, but running a Cystatin C test can give physicians reassurance and allow the patient to keep taking that effective bodybuilding supplement. 

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  6. Aldosterone, serum

    Aldosterone (ALD) is one of a group of connected hormones. They form the renin-angiotensin-aldosterone system; this system is activated when there is a decrease in blood flow to your kidneys following a drop in blood volume or blood pressure

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  7. Electrolyte Panel

    The electrolyte panel includes: Carbon dioxide, chloride, potassium, and sodium  

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  8. Uric Acid (Serum)

    Uric acid is a product produced by the body after the purines in many foods undergo the digestive process and are broken down inside the body. After this breakdown process, the uric acid travels through the bloodstream into your kidneys and most is actually eliminated through the urinary tract via urination. However, there are instances where you may have an excess of uric acid and are unable to excrete the bulk of this substance through urination. This could lead to gout-related issues.

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  9. Urinalysis

    The Urinalysis test panel screens for a variety of conditions including urinary tract infections ( UTI ), urinary bladder disease, kidney disease and diabetes. Tests included: Color, Appearance, Specific gravity, pH, Protein, Glucose, Occult blood, Ketones, Leukocyte esterase, Nitrite, Bilirubin, Urobilinogen, and Microscopic examination of urine sediment

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How to Get Kidney Function Tests to Prevent CKD

Chronic kidney disease (CKD) is a much larger health problem in the U.S. than many of you reading this may realize, which is why we’re going to answer all of your burning questions having to do with chronic kidney disease, including the stages, the symptoms, and the treatment options.

According to the Centers for Disease Control and Prevention (CDC)[1], the numbers are a little overwhelming:

  • 15 percent of U.S. adults have chronic kidney disease (37 million people)
  • Nine out of 10 adults in the U.S. don’t know they have CKD
  • One out of two adults in the U.S. with very low kidney function who are not already on dialysis don’t know they have chronic kidney disease

What’s the greatest takeaway from these three statistics? People who are at risk of getting CKD are not getting tested for it, which has negative long-term consequences.

Other important facts according to the CDC on chronic kidney disease include:

  • Chronic kidney disease is more common in people aged 65 years or older (38 percent) than in people aged 45–64 years (13 percent) or 18–44 years (7 percent)
  • Chronic kidney disease is more common in women (15 percent) than men (12 percent)
  • Chronic kidney disease is more common in African Americans (16 percent) than in whites (13 percent) or Asians (12 percent).
  • Around 14 percent of Hispanics have chronic kidney disease

Now that you know the facts and understand the severity of CKD, let’s answer some important questions about the disease.

  1. What is Chronic Kidney Disease?

CKD is a condition in which the kidneys gradually lose their ability to properly function. The kidneys can become damaged over time and this damage can lead to kidneys that don’t clean/filter a person’s blood as well as they should.

When the kidneys aren’t able to perform their job duties, this creates waste and water buildup in the body. As you might expect, this contributes to other health problems as this waste and water accumulate.

The biggest problem with chronic kidney disease is the lack of symptoms initially, as they tend to be more gradual. We’ll get into some of those symptoms in a minute.

  1. What Causes Chronic Kidney Disease?

The two main causes of chronic kidney disease, according to[2], are diabetes and high blood pressure.

Diabetes occurs when a person’s blood sugar levels are too high. When this happens, the person can experience damage to their organs and blood vessels.

High blood pressure, or hypertension, occurs when the pressure in the walls of the blood vessels increases to dangerous levels. High blood pressure can lead to increase risks of heart attack, stroke, and, of course, chronic kidney disease.

Other causes or risk factors include:

  • A family history of kidney problems
  • Glomerulonephritis – a group of diseases that cause inflammation and damage to the kidneys’ filtering capabilities
  • Polycystic kidney disease – an inherited disorder that causes cysts to develop in the kidneys
  1. What are the Five Stages of Chronic Kidney Disease?

They are five stages of CKD. According to Fresenius Kidney Care[3], these are the characteristics of each stage:

  1. Stage 1 – Kidney damage that still allows for normal kidney function.
  2. Stage 2 – Kidney damage with a mild loss of function.
  3. Stage 3 – Broken up into two stages, 3a includes mild to moderate loss of kidney function; 3b includes moderate to severe loss of kidney function.
  4. Stage 4 – Severe loss of kidney function.
  5. Stage 5 – Kidney failure, which will require dialysis and/or a kidney transplant.

       4. What are the Symptoms of Chronic Kidney Disease?


Unfortunately, the disease process can take years before symptoms are present, and this is true for CKD. Chronic kidney symptoms, according to, include:

  • Fatigue and loss of energy
  • Difficulty with concentration and focus
  • Lack of appetite
  • Difficulty sleeping
  • Muscle cramping at night
  • Swelling in feet and/or ankles
  • Puffiness around the eyes
  • Itchy, dry skin
  • Frequent urination, especially at night

Please remember, these symptoms can take years to develop. By the time you experience symptoms, you could be further along in the disease process than you might imagine. Symptoms for CKD don’t show up quickly like email. They take their time, like Pony Express.

  1. How is Chronic Kidney Disease Diagnosed?

Diagnosis of CKD is done using a combination of the following:

  • A thorough medical history
  • A physical examination
  • A urine dipstick test – measures pathological changes to a person’s urine
  • Blood testing, like measuring a person’s serum creatine level

There is some dispute today whether the creatinine test is really the best option, as the Cystatin C test may be better for muscular men.

Anyone who has the risk factors for chronic kidney disease should get tested and this includes older Americans who may not have diabetes or high blood pressure and those individuals in a higher-risk population, like African Americans, Hispanic Americans, Asian Americans, Pacific Islanders, and Native Americans.

  1. How to Treat Chronic Kidney Disease?

Chronic kidney disease treatment is more disease management than anything else since the damage cannot be fixed, according to The American Kidney Fund.[4]

For this reason, it’s important to stop the damage from getting worse. To this end, there are several treatment protocols that The American Kidney Fund recommends:

  • Stabilize your blood sugar, especially if you have diabetes
  • Maintain a healthy blood pressure
  • Eat a healthy diet – low salt, low fat
  • Exercise at least 30 minutes each day or engage in other physical activities
  • Maintain a healthy weight for your body type and height
  • Do not smoke or use tobacco products
  • Limit your alcohol consumption
  • Ask your doctor what medications may help control your CKD

The point worth remembering is this: You can catch CKD early and make the positive changes listed above or let your kidneys eventually fail. For this reason, prevention is always going to trump treatment, and this is very true when it comes to chronic kidney disease.

If you’re interested in preventing chronic kidney disease, simply follow those recommendations above before CKD develops.

  1. How Fast Does Chronic Kidney Disease Progress?

As you’ve learned already, chronic kidney disease can take years to develop before symptoms are present. However, according to Randy Chen, MD[5], a practicing nephrologist with San Mateo County, the progression of CKD depends on other factors.

Both the cause of your chronic kidney disease and your current stage are important. The results of your blood tests – which can help your doctor determine the trends in your kidney health – are equally important. And finally, Chen points out that while the progression can be slow, those in poorer health will experience faster progression of CKD.

  1. How Can Chronic Kidney Disease be Reversed?

Unfortunately, CKD cannot be reversed. However, it can be managed. The first step is to get tested and determine if you have chronic kidney disease. All subsequent steps involve the management/treatment options we listed above in the chronic kidney disease treatment section.

            9. Can Chronic Kidney Disease Cause UTI?


UTI is short for urinary tract infections. Germs and bacteria can get into the urinary tract and multiply. The result is usually a combination of swelling, redness, and pain. The greater problem is that if left untreated, it can get worse and cause a more serious infection. However, it does not appear that CKD causes UTIs.

          10. How Long Can You Live with Chronic Kidney Disease?


According to, “how long you can live with CKD depends on your age, other health problems, and how involved you become in your care.”

Most people who have CKD will never have their kidneys fail and many people who do have kidney failure can still live for decades afterward with dialysis or a kidney transplant.

Advances in healthcare have come a long way. There are better drugs for chronic kidney disease, more knowledge about the disease, and better dialysis machines helping people manage their CKD.

However, according to[6], the most important factor in determining how your CKD will progress is you. If you take responsibility for your health and make the necessary changes, you can live well with chronic kidney disease. And do you know where that personal responsibility begins? Getting tested!

We’re going to end this post with words of advice from Fresenius Kidney Care:

Getting tested to check your kidney health is critical to your current and future well-being. Whether you and your doctor are seeking a diagnosis or monitoring how well your treatment plan is working, acting early is always best. For CKD, the sooner your doctor can confirm a diagnosis, the earlier you can get started on an effective treatment plan to help preserve kidney function and slow progression.

If you’re interested in getting tested for chronic kidney disease, Discounted Labs has six laboratory tests that can measure your kidney function:

CMP - Comprehensive Metabolic Panel

The comprehensive metabolic panel or chemical screening, (CMP) is a panel of 14 blood tests which serves as an initial medical screening tool to review overall health. The CMP functions as a check for kidney function, liver function, and electrolyte and fluid balance.

Aldosterone, Serum

Aldosterone (ALD) is one of a group of connected hormones. They form the renin-angiotensin-aldosterone system; this system is activated when there is a decrease in blood flow to your kidneys following a drop in blood volume or blood pressure such as during heavy bleeding, or sodium levels fall below healthy levels.

Cystatin C with EGFR Blood Test

The cystatin C test (which also includes estimated creatinine clearance eGFR) can be done along with creatinine or creatinine clearance test in cases where those tests aren’t appropriate. Since the concentration of cystatin C in the blood will not change due to infection or inflammation and isn’t affected by body weight, drugs, or diet - cystatin C level could be a more reliable indicator of kidney health than creatinine.

Electrolyte Panel

The electrolyte panel includes carbon dioxide, chloride, potassium, and sodium.

Uric Acid (Serum)

Uric acid is a product produced by the body after the purines in many foods undergo the digestive process and are broken down inside the body. After this breakdown process, the uric acid travels through the bloodstream into your kidneys, and most are actually eliminated through the urinary tract via urination. Excess uric acid may indicate CKD.


The Urinalysis test screens for a variety of conditions including urinary bladder disease, kidney disease, and diabetes. Many systemic illnesses can affect results and significant deviations from the normal range may require further evaluation by your physician.


Be kind to your kidneys. Get tested today!


Sources & References

1 Centers for Disease Control and Prevention, Chronic Kidney Disease in the United States, 2019

2, Chronic Kidney Disease (CKD) Symptoms and Causes

3 Fresenius Kidney Center, Diagnosis and Testing for Chronic Kidney Disease

4 The American Kidney Fund, Chronic kidney disease (CKD)

5 Randy Chen, MD, The American Kidney Fund

6, Learn About Kidney Disease FAQ