What Does It Mean If eGFR Is High?

Medically Reviewed on 10/27/2022
renal (kidney) health
Glomerular filtration rate (GFR) is a test that determines how well your kidneys are functioning.

Glomerular filtration rate (GFR) is a crucial marker of renal (kidney) health.

Estimated GFR (eGFR) is a mathematical construct based on the age, sex, ethnicity, and serum creatinine level of a person. This is typically determined through the laboratory's analysis of the blood sample and reported together with the serum creatinine result.

  • “Normal” GFR is typically greater than 90 ml/min/1.73 m2, indicating normal kidney function.
  • In the initial stages of kidney disease, however, the eGFR could be normal despite the presence of some signs of kidney damage, such as protein in the urine.
  • According to the National Kidney Foundation, the normal range is between 90 and 120 mL/min/1.73 m2.

What is GFR?

Glomerular filtration rate (GFR) is a blood test that measures how well the kidneys are functioning. Glomeruli are microscopic filters found in the kidneys. These filters aid in the removal of waste and extra fluid from the blood. Blood flow through these filters is measured by a GFR test. A GFR can be directly assessed, but it is a challenging procedure that needs skilled experts.

The most common method to express GFR is the estimated GFR test or eGFR.

  • To provide an estimate, your practitioner will utilize a process called the GFR calculator.
  • The GFR calculator is a particular kind of mathematical formula that determines the rate of filtration of blood by the kidneys.
  • This is accomplished by using your personal information, such as age, gender, height, weight, and ethnicity.
  • The findings of the blood test analyze the amount of creatinine, a waste product that is filtered by the kidneys.
  • Medical professionals gauge eGFR in milliliters of blood that has been cleansed per minute per unit of body surface (mL/min/1.73m2).

What is the purpose of the eGFR test?

The early-stage renal disease normally has no symptoms. Estimated glomerular filtration rate (eGFR) testing could be advised by your doctor if you are at increased risk of developing renal disease.

Risk elements for chronic kidney disease (CKD) include:

CKD in its later stages does have symptoms. If you have any of the following signs, you may require an eGFR test:

What might affect your test result?

Your test outcome may not be as precise if you fall under any of the following categories:

  • Severely undernourished, underweight, or have an illness that causes muscle wasting
  • Significantly overweight
  • Possess a neuromuscular condition
  • Take any medications, such as chemotherapies or renal medications
  • Consume lots of meat
  • Take creatine supplements
  • Pregnant
  • Possess above-average muscle mass, such as a bodybuilder

SLIDESHOW

Kidney Stones: Symptoms, Causes, and Treatment See Slideshow

What do your test results mean?

Your age, gender, medical history, and other factors may affect the test findings. Depending on the lab utilized, the results of your test may change. Consult your doctor to learn the implications of your test results for you.

Kidney disease has five stages. Based on the degree of kidney damage indicated by your estimated glomerular filtration rate (eGFR), your healthcare professional defines your stage.

  1. Stage I (eGFR of 90 mL/min/1.73m2 or higher): Indicates possible kidney damage (protein in the urine) with normal renal function.
  2. Stage II (eGFR between 60 and 89 mL/min/1.73m2): Indicates renal injury combined with a slight reduction of kidney function.
  3. Stage III (eGFR between 30 and 59 mL/min/1.73m2): Minimal to moderate renal functional loss.
  4. Stage IV (eGFR between 15 and 29 mL/min/1.73m2): Severe impairment of kidney function.
  5. Stage V (eGFR below 15 mL/min/1.73m2): Indicates kidney failure. It is potentially fatal at this level. You will require a kidney transplant or dialysis (a procedure that filters out wastes from your blood).

What are the risks associated with this test?

The risk of having your blood taken is negligible. The dimensions of veins and arteries differ among people and from one side of the body to the other. It could be more challenging to take a blood sample from some people than from others.

The following are a few minor additional dangers that may be present when withdrawing a blood sample:

  • Bleeding excessively
  • Fainting or experiencing dizziness
  • Several punctures to find veins
  • Hematoma (blood accumulating under the skin)
  • Infection (whenever the skin is broken there can be a minor possibility for skin infection)
Medically Reviewed on 10/27/2022
References
Image Source: iStock image

Estimated Glomerular Filtration Rate (eGFR). https://www.kidney.org/atoz/content/gfr Kidney Failure Risk Factor: Estimated Glomerular Filtration Rate (eGFR). https://www.kidney.org/content/kidney-failure-risk-factor-estimated-glomerular-filtration-rate-egfr

What Is a Glomerular Filtration Rate (GFR)? https://www.webmd.com/a-to-z-guides/glomerular-filtration-rate

Glomerular filtration rate. https://www.ucsfhealth.org/medical-tests/glomerular-filtration-rate

Glomerular Filtration Rate. https://www.urmc.rochester.edu/encyclopedia/content.aspx?contenttypeid=167&contentid=glomerular_filtration_rate