Glomerular filtration rate (GFR; Estimated GFR; eGFR) is a test used to check how well the kidneys are working. Particularly, it approximates how much blood passes through the glomeruli each minute. Glomeruli are the small filters in the kidneys that filter waste from the blood.
Normal Glomerular Filtration Rate
According to the National Kidney Foundation, estimated nornal results range from 90 to 120 mL/min/1.73 m2. Older people will have lower than typical GFR levels, since GFR decreases with age.
Regular worth varieties may differ somewhat amongst different laboratories. Some labs use different measurements or test different samples. Speak to your doctor about the significance of your particular test results.
Estimated Glomerular Filtration Rate
The following table summarizes estimated GFR and the stages of kidney damage:
| KIDNEY DAMAGE STAGE | DESCRIPTION | ESTIMATED GFR (ML/MIN/1.73M2) | OTHER FINDINGS |
|---|---|---|---|
| 1 | Normal or minimal kidney damage with normal GFR | 90+ | Protein or albumin in urine may be high, cells or casts rarely seen in urine (see Urinalysis) |
| 2 | Mild decrease in GFR | 60-89 | Protein or albumin in urine may be high, cells or casts rarely seen in urine |
| 3 | Moderate decrease in GFR | 30-59 | |
| 4 | Severe decrease in GFR | 15-29 | |
| 5 | Kidney failure | <15 |
Decreased Glomerular Filtration Rate Meaning
Levels listed below 60 mL/min/1.73 m2 for 3 or more months are a sign of chronic kidney disease. A GFR lower than 15 mL/min/1.73 m2 is a sign of kidney failure and requires instant medical attention.
How Is Glomerular Filtration Rate Test Performed
A blood sample is required.
The blood sample is sent to a lab. There, the creatinine level in the blood sample is evaluated. The laboratory specialist combines your creatinine level with numerous other factors to approximate your GFR. Various solutions are used for grownups and children. The formula includes some or all the following:
- Age
- Blood creatinine measurement
- Ethnic culture
- Gender
- Height
- Weight
The creatinine clearance test, which includes a 24-hour urine collection, can also provide an estimate of kidney function.
How to Prepare for the GFR Test
Your health care provider may ask you to briefly stop any medicines that might impact the test results. These consist of antibiotics and stomach acid medications.
Be sure to inform your provider about all the medicines you take. Do not stop taking any medication before speaking with your doctor.
Inform your doctor if you are pregnant or believe you might be. GFR is affected by pregnancy.
How Glomerular Filtration Rate Test will Feel
When the needle is inserted to draw blood, some people feel moderate pain. Others feel just a prick or stinging. Later, there might be some throbbing or a small swelling. This soon goes away.
Why GFR Test is Performed
The GFR test determines how well your kidneys are filtering the blood. Your doctor might order this test if there are signs that your kidneys are not working well. It might likewise be done to see how far kidney disease has advanced.
The GFR test is advised for people with chronic kidney disease. It is likewise suggested for individuals who may get kidney disease due to:
- Diabetes
- Family history of kidney disease
- Regular urinary tract infections
- Heart disease
- High blood pressure
- Urinary obstruction
Risks
Veins and arteries differ in size from one patient to another and from one side of the body to the other. Getting a blood sample from some people may be harder than from others.
Other dangers connected with having blood drawn are minor, however can include:
- Excessive bleeding
- Passing out or feeling lightheaded
- Hematoma (blood building up under the skin).
- Infection (a small risk at any time the skin is broken).