eGFR Blood Test

If you are concerned about your kidney health, one of the most important tools at your disposal is the eGFR or Estimated Glomerular Filtration Rate blood test. This test uses a mathematical equation to estimate your kidney function based on factors like age, race, gender, creatinine levels, and levels of cystatin C.

If your eGFR levels are low, it could be an early sign of kidney disease or other kidney issues. The eGFR blood test is crucial for assessing loss of kidney function and determining the stage of any potential renal disease.

It can also help identify other problems such as dehydration, urinary tract blockage or medication reactions that may be affecting your kidneys.

Early detection and management of kidney disease can significantly improve outcomes, making this test an essential tool for individuals with risk factors or symptoms of kidney issues.

In this article, we'll explore what eGFR is and how it's calculated, along with the factors that can affect its accuracy. We'll also look at other tests used to diagnose kidney disease and discuss why early detection is so important when it comes to managing this condition effectively. Learning how to manage chronic kidney disease gets easier over time.

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Can you have a low EGFR and not have CKD

Key Takeaways

  • eGFR is a measure of kidney health that assesses kidney function estimated through a blood test and other factors.
  • A normal eGFR is 60 or higher, and an eGFR less than 60 for three months or more may indicate kidney problems.
  • Lower eGFR increases the risk of CKD progression to kidney failure, and early detection of kidney disease improves chances of slowing or stopping progression.
  • Lifestyle steps can manage kidney disease, such as diet, exercise, lowering blood pressure, and changing sleep and stress management habits, and it is important to talk to a doctor about options and ask questions if concerned about eGFR test results.
what is eGFR in blood test

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What is eGFR?

eGFR, or estimated glomerular filtration rate, is a mathematical equation used to estimate level of kidney function based on factors like age, race, gender, and creatinine levels in the blood. The eGFR calculation takes into account a person's age and body size because these factors can impact their creatinine levels.

In a nutshell, it’s an equation based on several factors, including a blood test, to determine your level of kidney function and your stage of kidney disease (renal diet restrictions by stage of CKD).

eGFR estimates how much blood passes through the glomeruli each minute. Glomeruli are the tiny filters in the kidneys that filter waste from the blood. Your kidneys are a filtering organ. They remove waste and extra fluid from your body. In fact, they filter about 200 quarts of blood each day and through that process create up to two quarts of urine.

The glomerulus is the key part of this filtration system. When you’re evaluated for your filtration rate, it’s estimating the effectiveness of your kidneys.

Creatinine is produced by normal breakdown of muscles and is filtered through the kidneys, so higher creatinine levels may indicate decline in kidney function.

The normal range for eGFR is 90 or above for the first stage kidney disease and 60-89 for stage 2 kidney function. If your eGFR falls below 60 for three months or more, it may indicate chronic kidney disease (CKD).

However, it's important to note that eGFR has accuracy limitations as it doesn't take into account individual variations in muscle mass and hydration status. Enough water intake and being well hydrated before your blood draw can provide a more accurate GFR level.

It's crucial to talk to your doctor about what your eGFR results mean for your overall health and any necessary steps you should take to keep kidney function intact. Early detection of kidney disease can improve chances of slowing or stopping progression.

Factors Affecting eGFR

Factors like your age, muscle mass, and even hydration level (fluids to hydrate with kidney disorder) can significantly impact the accuracy of your kidney function results. Creatinine levels in the blood are used to calculate eGFR, but these levels can vary depending on your muscle mass.

This means that if you have more muscle mass than average for someone your age and gender, your creatinine levels may be higher and falsely indicate reduction of kidney function.

Hydration status is also a crucial factor when it comes to eGFR results. Good water intake before having your blood sample drawn for the test can help ensure accurate results. If you're dehydrated, however, this can cause your creatinine levels to spike and make it appear as though you have lower kidney function than you actually do.

Age and sex are other essential factors to consider when interpreting eGFR results. As we get older, our kidney function naturally declines over time.

Additionally, women tend to have slightly lower eGFR values than men due to differences in muscle mass. It's important to keep these factors in mind when evaluating your eGFR results with a healthcare professional so that any necessary adjustments or interventions can be made promptly.

Tests for Kidney Function

If you're worried about potential loss of kidney function, there are several tests your doctor may use to evaluate it. Besides the eGFR blood test, urine albumin and creatinine levels can also be measured to detect kidney damage and assess how well the kidneys are functioning.

Urine albumin measures the amount of the protein albumin in urine, which is an early sign of kidney disease. Dehydration can affect these tests' accuracy, so staying hydrated is crucial before testing.

Certain medications can also interfere with results, so it's essential to inform your doctor about any prescriptions or dietary supplements you're taking. Additionally, fasting or avoiding certain foods or activities may be necessary for some tests (avoid end stage renal disease).

Regularly monitoring kidney function through these tests can help diagnose and manage kidney disease early on. It's important to talk to a health care provider if you have health conditions or risk factors for kidney disease like diabetes or high blood pressure.

By staying informed and taking steps like hydration and medication management, you can maintain healthy kidneys and prevent further damage.

Risk Factors for Low eGFR

Risk factors for low eGFR include preexisting conditions like diabetes, high blood pressure, cardiovascular disease, and a family health history of kidney disease all contribute to your risk of having kidney failure.

These are all risk factors for having decline in kidney function. There are other risks as well, such as urinary blockage and dehydration.

It's important to be aware of these risks because they can affect your eGFR blood test results. Dehydration can cause low eGFR levels by making the blood more concentrated, which affects creatinine levels. That's why it's important to have adequate water intake before getting an eGFR blood test.

If you have a family medical history of kidney failure or cardiovascular disease, it means that you may have a higher risk for developing kidney problems later in life. It's important to get regular check-ups and monitor your kidney function if you have these risk factors.

Urinary blockages can lead to low eGFR levels by preventing urine from flowing out properly. If you experience symptoms like pain or discomfort during urination, talk to your doctor right away as this could be a sign of urinary blockage.

Symptoms of Low eGFR

Fatigue, swelling, and inflammation, and increased urination are common symptoms of low eGFR levels. When your kidneys aren't functioning properly, they can't filter waste products from the blood as effectively as they should. This can lead to a buildup of toxins in your body, which can cause you to feel tired and weak.

Other possible symptoms (progression of symptoms for CKD) can be dry and itchy skin, trouble sleeping, poor appetite, trouble concentrating, and muscle cramps.

Urine may appear dark or foamy due to protein leakage into the urine, which is another symptom of kidney damage. Some patients may also observe bloody urine. 

Low eGFR levels can also lead to anemia, which occurs when there aren't enough red blood cells in your body. Anemia can cause weakness, shortness of breath, pale skin coloration, and other symptoms that interfere with daily activities, such as work or exercise.

In any case, it is also important to note early-stage CKD may have no signs or symptoms. Hence, having routine blood tests and check-ups with your healthcare professionals is important for early initial diagnosis and to  slow progression of CKD. 

If chronic kidney disease runs in your family or you’re concerned about kidney disease, look for some telltale symptoms including:


Fatigue or lethargy is a common symptom of impaired or poor kidney function. If your kidneys aren’t able to properly filter waste, it can back up in your body and cause issues throughout your entire body.

Swelling and Inflammation

In addition to fatigue, you may also experience edema or swelling due to fluid buildup in the body. This can occur in various areas, such as the legs, ankles, feet, face, or hands.

Increased Urination

Increased urination, especially at night, is a common problem for many conditions. And it’s a side effect of some medications that you may already be on. However, if you’re experiencing increased urination along with fatigue and/or swelling, it’s time to go to your doctor.

It's important to talk to your doctor if you're experiencing any signs of kidney problems so they can perform laboratory tests and determine whether further evaluation is necessary for kidney function management and making a treatment plan.

Lifestyle Changes for Kidney Health

Improving your lifestyle habits can help manage kidney disease and prevent further damage. One of the most important changes you can make is to adopt a healthy diet that includes dietary restrictions to protect your kidneys.

Avoid high-sodium foods, processed meats, and sugary drinks. Instead, opt for fresh fruits and vegetables, lean proteins such as chicken or fish, and whole grains. Limiting your dietary protein intake may also be beneficial.

Exercise is another key component in managing kidney disease. Regular physical activity not only helps control weight but also improves cardiovascular health and lowers blood pressure - both critical factors in preventing kidney damage progression.

Consult with your health care professional before starting any exercise routine and aim for at least 30 minutes of moderate-intensity exercise per day.

Hydration is crucial in maintaining kidney health. Staying well hydrated ensures proper blood flow to the kidneys, which aids in flushing out waste products from the body. Drinking water regularly throughout the day is recommended for optimal hydration levels.

Proper sleep management and stress reduction techniques such as meditation or deep breathing exercises can also aid in reducing inflammation that may lead to further kidney damage over time.

Adopting these lifestyle changes may seem daunting at first but remember that small steps taken daily add up to significant progress over time. Consult with your healthcare provider about additional resources available to support you on this journey towards better kidney health.

eGFR Levels and CKD Stages

Now that you have learned about the lifestyle changes that can help improve your kidney health, let's discuss eGFR levels and CKD stages (food for your stage of chronic kidney disease). As mentioned earlier, eGFR is a measure of kidney function estimated through a blood kidney test and other factors.

Normal kidney function is 60 or higher, while an abnormal eGFR less than 60 for three months or more may indicate kidney problems and increase the risk of CKD progression to kidney failure.

To better understand the different stages of CKD based on eGFR levels, here is a table that shows how they are classified:

1Kidney damage with normal or high GFR (eGFR >90)
2Mild decrease in GFR (eGFR = 60-89)
3aModerate decrease in GFR (eGFR = 45-59)
3bModerate decrease in GFR (eGFR =30-44)
4Severe decrease in GFR (eGFR =15-29)
5Kidney failure (eGRF <15)

If you have been given a definitive diagnosis of CKD, it's important to work closely with your healthcare team to manage your condition. A personalized treatment plan may include medication management (diet vs medication for CKD improvement), lifestyle interventions such as diet and exercise changes, and regular kidney health monitoring.

It's also crucial to avoid certain medications like non-steroidal anti-inflammatory drugs (NSAIDs) and contrast dye if you have CKD. With early detection and proper management, you can slow down the progression of CKD and maintain optimal kidney function for as long as possible.

Other Tests for Kidney Disease

Let's explore some additional ways to detect and diagnose kidney disease beyond the standard blood test. Here are some other tests that your doctor may recommend:

  • Imaging tests: Ultrasound, CT scans, MRI, or X-rays can be used to look at the kidneys and check for any structural abnormalities or other evidence of kidney damage.
  • Biopsy considerations: In certain cases, a small piece of kidney tissue may need to be removed and examined under a microscope to determine the cause of kidney disease. This is called a kidney biopsy.
  • uACR testing alternatives: In addition to eGFR and serum creatinine blood test, your doctor may also order a urine albumin-to-creatinine ratio (uACR) test. This measures the amount of urine protein and can detect early signs of kidney damage.
  • Nephrologist involvement: Depending on how advanced your kidney disease is, you may need to see a specialist called a nephrologist, a specialist doctor for treatment and diagnosis of kidney disease. 

Other tests that your kidney doctor may request include serum cystatin, blood urea nitrogen and urine tests like 24-hour urine collection.

It's important to note that these tests have potential dietary restrictions or preparation requirements. Your primary care provider will provide guidance on what you should or shouldn't eat before these tests.

It's also crucial to maintain regular communication with your healthcare team about any concerns you have regarding your diagnosis so they can provide optimal care for you.

Managing Kidney Disease

To manage your kidney disease, you can take steps to maintain a healthy lifestyle and work closely with your healthcare team.

Dietary modifications are one of the most important aspects of managing kidney disease, as certain foods may need to be limited or avoided altogether. Your doctor or dietitian can help create a personalized meal plan that takes into account your specific needs and preferences.

Exercise routines can also play a significant role in managing kidney disease. Regular physical activity can help improve cardiovascular health and maintain muscle mass, which is especially important for individuals with low eGFR levels.

Additionally, stress relief techniques such as meditation or yoga may also be helpful in managing symptoms related to kidney disease.

Medication management is another crucial component of managing kidney disease (diet vs medication for CKD improvement). Depending on your individual situation, medications may be prescribed to control blood pressure, lower blood cholesterol levels, or manage other chronic conditions that could negatively impact kidney function.

Finally, hydration strategies should also be considered when managing kidney disease. Staying properly hydrated is essential for maintaining good overall health and avoiding complications associated with dehydration.

By making these lifestyle changes and working closely with your healthcare team, you can take control of your kidney disease and reduce the risk of further damage to your kidneys.

Remember to stay informed about your condition by asking questions and discussing any concerns with your doctor or specialist regularly.

Importance of Early Detection

Don't wait until it's too late to detect kidney disease, because taking early action can improve your chances of slowing or even stopping its progression.

Early intervention is key to preventing progression and maintaining kidney function. Regular monitoring frequency is important for those at risk, especially those with diabetes, high blood pressure, and a family history of kidney failure.

If you've been diagnosed with kidney disease, there are treatment options available that can help manage the condition. Your doctor may recommend lifestyle changes such as diet modifications, exercise programs, and stress management techniques. Patient education is also crucial in understanding the condition and managing its symptoms effectively.

Remember that early detection is essential in managing kidney disease effectively. Get your kidneys checked regularly by having an eGFR test done at least once a year.

Follow your healthcare provider's recommendations for treatment and lifestyle modifications to keep your kidneys functioning properly. With the right care and attention, you can live a healthy life despite having kidney disease.

FAQs EGFR Blood Test

Is GFR the same as eGFR?

You may see two different terms or abbreviations used. They are GFR or Glomerular Filtration Rate and eGFR or Estimated Glomerular Filtration Rate. They are different terms to express kidney function and show if you have healthy kidneys.

GFR is an indicator of renal function and may also be referred to as your kidney function. GFR represents the amount of blood filtered by your glomeruli each minute.

eGFR is estimated GFR and is a mathematically derived entity based on your serum levels of creatinine, age, sex, and race.

Can eGFR be affected by other medical conditions?

Medical factors and comorbidities can impact the accuracy of eGFR results. Age is an important factor that affects eGFR, as older individuals tend to have lower GFR levels due to decreased kidney function over time.

Dehydration can also affect eGFR results by causing a temporary decrease in kidney function. In addition, certain medical conditions such as muscle disorders (such as muscle wasting diseases or neuromuscular disorders) or liver disease may lead to less accurate interpretation of eGFR readings.

It's important to discuss any comorbidities with your healthcare provider before taking an eGFR test in order to ensure accurate result interpretation.

Is it possible to improve eGFR levels through lifestyle changes?

If you're looking to improve your eGFR levels through lifestyle changes, there are several things you can do.

. First and foremost, make dietary modifications by eating a kidney-friendly diet that's low in sodium (how much sodium per day for renal diet), phosphorus, and protein.

. Incorporate exercise routines into your daily routine to maintain a healthy weight and lower blood pressure.

. Keep yourself well-hydrated by drinking plenty of water and avoiding sugary drinks.

. Ensure that you have good sleep patterns by getting enough restful sleep each night.

. Finally, manage stress effectively through techniques such as meditation or yoga.

All of these strategies can help to reduce the risk of kidney disease or slow its progression for kidney patients.

How often should someone get their kidneys checked if they have low eGFR?

If you have low eGFR, it's recommended to monitor your kidney function regularly with simple blood tests and urine albumin tests. The monitoring frequency may vary depending on your current health status and risk factors for kidney disease.

Your doctor may also recommend alternative tests such as imaging or a kidney biopsy if needed.

It's important to work closely with your healthcare team to manage your condition and prevent further damage to your kidneys.

Are there any medications that can improve eGFR levels?

Unfortunately, there aren't any kidney medicines that have been shown to directly improve eGFR levels. However, there are drug options that can help manage underlying conditions that contribute to low eGFR, such as blood pressure medications, diabetes agents, and heart disease medicines.

Supplement use and nutritional interventions may also be helpful in managing kidney disease, but it's important to speak with a healthcare provider before starting any supplements or making significant changes to your diet.

Lifestyle modifications such as quitting smoking, maintaining a healthy weight, exercising regularly, and controlling blood pressure (high blood pressure and kidney disease) and blood sugar through diet and medication can also help slow the progression of kidney disease and improve overall health.

Is it possible to have kidney disease without low eGFR levels?

It's possible to have kidney disease without low eGFR levels. Kidney function can be evaluated using alternative markers such as urine albumin and albumin/creatinine ratio tests.

Additionally, age-related changes and ethnic disparities can impact eGFR levels, making it less reliable for diagnosing kidney disease in some populations. Comorbid conditions such as diabetes or high blood pressure can also affect kidney function even if eGFR levels appear normal.

Therefore, it's important for individuals with risk factors or symptoms of kidney disease to consult a healthcare provider for proper evaluation and monitoring, which may include additional tests beyond the eGFR blood test. Early detection and management of kidney disease is key to preventing further damage and maintaining overall health.

When In Doubt About Your eGFR, Consult A Doctor!

It’s always important to talk with your doctor about options and to ask questions. They can help you navigate your diagnosis.

Keep in mind that if you get an eGFR test result that indicates kidney disease, there are additional tests to take to confirm this diagnosis. If your eGFR levels are low, don't panic. There are many other tests available to diagnose kidney disease and determine the stage of the disease.

You also have control in this process. Lifestyle habits make a significant impact on the quality of your life and the health of your kidneys.

Early detection and management of kidney disease (how to manage chronic kidney disease) can significantly improve outcomes, so it's essential to take care of your kidneys and get regular check-ups with your doctor.

Remember that managing kidney disease involves a combination of medication management, lifestyle changes like diet and exercise, and monitoring of symptoms.

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  1. Franz Green says:

    My Creatinine results on my latest blood test was 1.35 and my eGFR was 47 and I have been diagnosed with having stage 3 chronic kidney disease. I also have heart disease and I am a diabetic with an A1c of 8.3. My blood pressure is good (in the 120-140 range) and I am 76 years old. What can I do to prevent my kidneys from getting worse or even reverse the downward trent if even possible?

  2. Minnie Moline says:

    My Lab test always has eGFR NON-AFR AMERICAN AND eGFR AFRICAN AMERICAN. Why does the test have this. I am not African American.