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Glomerular filtration rate (GFR) is a test used to check how well the kidneys are working. Specifically, it estimates how much blood passes through the tiny filters in the kidneys, called glomeruli, each minute.
See also:
Alternative NamesGFR; Estimated GFR; eGFR
How the test is performedBlood is drawn from a vein, usually from the inside of the elbow or the back of the hand. The site is cleaned with germ-killing medicine (antiseptic). The health care provider wraps an elastic band around the upper arm to apply pressure to the area and make the vein swell with blood.
Next, the health care provider gently inserts a needle into the vein. The blood collects into an airtight vial or tube attached to the needle. The elastic band is removed from your arm.
Once the blood has been collected, the needle is removed, and the puncture site is covered to stop any bleeding.
In infants or young children, a sharp tool called a lancet may be used to puncture the skin and make it bleed. The blood collects into a small glass tube called a pipette, or onto a slide or test strip. A bandage may be placed over the area if there is any bleeding.
The blood sample is sent to a lab, where the creatinine level is tested. The lab specialist uses combines your creatinine level with several other factors to estimate your glomerular filtration rate (GFR). Different formulas are used for adults and children. The formula will include some or all of the following:
- Age
- Creatinine measurement
- Gender
- Height
- Race
- Weight
Certain drugs can interfere with test results. Tell your doctor about all medicines you are taking, including over-the-counter ones.
How the test will feelWhen the needle is inserted to draw blood, some people feel moderate pain, while others feel only a prick or stinging sensation. Afterward, there might be some throbbing.
Why the test is performedThe GFR test measures how well your kidneys are filtering a waste called creatinine, which is produced by the muscles. When the kidneys aren't working as well as they should, creatinine builds up in the blood.
Your doctor may order this test if there are signs that your kidneys are not working properly. It may also be done to see how far kidney disease has progressed.
The test is recommended for people with chronic kidney disease and those at risk for it due to:
- Diabetes
- Family history of kidney disease
- Frequent urinary tract infections
- Heart disease
- High blood pressure
- Urinary blockage
According to the National Kidney Foundation, normal results range from 90 - 120 mL/min. Older people will have lower normal GFR levels, because GFR decreases with age.
Normal value ranges can vary slightly among different laboratories. Talk to your doctor about what your specific test results mean.
What abnormal results meanLevels below 60 mL/min for 3 or more months are a sign of chronic kidney disease. Those with GFR results below 15 mL/min are a sign of kidney failure.
What the risks areVeins and arteries vary in size from one patient to another and from one side of the body to the other. Obtaining a blood sample from some people may be more difficult than from others.
Other risks associated with having blood drawn are slight, but can include:
- Excessive bleeding
- Fainting or feeling light-headed
- Hematoma (blood accumulating under the skin)
- Infection (a slight risk any time the skin is broken)
The creatinine clearance test, which involves a 24-hour urine collection, can also provide an estimate of kidney function. However, this method is not always accurate.
GFR can increase during pregnancy.
ReferencesK/DOQI clinical practice guidelines for chronic kidney disease: evaluation, classification, and stratification. Kidney Disease Outcome Quality Initiative. Am J Kidney Dis. 2002;39(2 Suppl 1):S1-246.
Johnson CA, Levey AS, Coresh J, Levin A, Lau J, Eknoyan G. Clinical practice guidelines for chronic kidney disease in adults: Part II. Glomerular filtration rate, proteinuria, and other markers. Am Fam Physician. 2004;70:1091-1097.
Snyder S, Pendergraph B. Detection and evaluation of chronic kidney disease. Am Fam Physician. 2005;72:1723-1732, 1733-1734.
Wiki User
∙ 13y ago
Wiki User
∙ 12y agoGlomerular filtration rate (GFR) is a test used to check how well the kidneys are working. Specifically, it estimates how much blood passes through the tiny filters in the kidneys, called glomeruli, each minute.
See also:
Alternative NamesGFR; Estimated GFR; eGFR
How the test is performedA blood sample is needed. For information on how this is done, see: Venipuncture
The blood sample is sent to a lab, where the creatinine level is tested. The lab specialist uses combines your creatinine level with several other factors to estimate your glomerular filtration rate (GFR). Different formulas are used for adults and children. The formula will include some or all of the following:
- Age
- Creatinine measurement
- Gender
- Height
- Race
- Weight
Certain drugs can interfere with test results. Tell your doctor about all medicines you are taking, including over-the-counter ones.
How the test will feelWhen the needle is inserted to draw blood, some people feel moderate pain, while others feel only a prick or stinging sensation. Afterward, there might be some throbbing.
Why the test is performedThe GFR test measures how well your kidneys are filtering a waste called creatinine, which is produced by the muscles. When the kidneys aren't working as well as they should, creatinine builds up in the blood.
Your doctor may order this test if there are signs that your kidneys are not working properly. It may also be done to see how far kidney disease has progressed.
The test is recommended for people with chronic kidney disease and those at risk for it due to:
- Diabetes
- Family history of kidney disease
- Frequent urinary tract infections
- Heart disease
- High blood pressure
- Urinary blockage
According to the National Kidney Foundation, normal results range from 90 - 120 mL/min/1.73 m2. Older people will have lower normal GFR levels, because GFR decreases with age.
The examples above are common measurements for results of these tests. Normal value ranges may vary slightly among different laboratories. Some labs use different measurements or test different samples. Talk to your doctor about the meaning of your specific test results.
What abnormal results meanLevels below 60 mL/min/1.73 m2 for 3 or more months are a sign of chronic kidney disease. A GFR result below 15 mL/min/1.73 m2 is a sign of kidney failure and requires immediate medical attention.
What the risks areVeins and arteries vary in size from one patient to another and from one side of the body to the other. Obtaining a blood sample from some people may be more difficult than from others.
Other risks associated with having blood drawn are slight, but can include:
- Excessive bleeding
- Fainting or feeling light-headed
- Hematoma (blood accumulating under the skin)
- Infection (a slight risk any time the skin is broken)
The creatinine clearance test, which involves a 24-hour urine collection, can also provide an estimate of kidney function. However, this method is not always accurate.
GFR can increase during pregnancy.
ReferencesBazari H. Approach to the patient with renal disease. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 115.
Israni AK, Kasiske BL. Laboratory assessment of kidney disease: clearance, urinalysis, and kidney biopsy. In: Brenner BM, ed. Brenner and Rector's The Kidney. 8th ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 23.
Reviewed ByReview Date: 09/19/2011
David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine; Herbert Y. Lin, MD, PHD, Nephrologist, Massachusetts General Hospital; Associate Professor of Medicine, Harvard Medical School. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.
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How does pressure affect filtration?
Pressure will increase the filtration rate all other things being equal.
How do you define ct rate?
CT rate or a corporation tax rate is the rate of tax due from company profits.
Is acceleration the rate of change of the rate of change of position?
no its speed that definds the rate change of position
What is the rate of Chang of velocity?
The rate of change of velocity is acceleration.
What is rate of deceleration?
The rate of deceleration is how quickly something is slowing down.
How does glomerular hydrostatic pressure effect filtration rate?
As the Glomerular Hydrostatic Pressure (GHP) goes up, the Filtration rate goes up.
What does the medical abbreviation GFR mean?
Glomerular Filtration RateThe GFR stands for glomerular filtration rate, and assesses kidney function.
Is the kidney functional when the glomerular filtration rate is zero?
no
What is injected to measure glomerular filtration rate?
inulin
What does the medical abbreivation GRF mean'?
Glomerular filtration rate
What is the normal adult glomerular filtration rate?
Glomerular filtration rate is the rate at which fluid is filtered by the kidneys. The normal rate for humans is 125mL/min or 180L/day. The fluid that is filtered (and not reabsorbed later) is excreted as urine.
What Polysaccharide substance is used to determine Glomerular Filtration Rate?
Yes
What is the effect of constricted arterioles in the glomerular filtration rate?
Decreasing the diameter of the efferent arteriole would increase the hydrostatic pressure inside the glomerulus and effectively increase the glomerular filtration rate. If you increase the diameter of the afferent arteriole you would achieve the same effect.
What is the glomerular filtration rate per day normally about?
on average, about 18 liters.
Where can one find the glomerular filtration rate?
Glomerular filtration rate (GFR) is a measurement of how well one's kidneys are functioning. It is typically estimated on the basis of serum creatinine levels. One can learn their estimated GFR by visiting their physician.
What is glomerular filtrate?
Glomerular filtration rate is the rate at which fluid is filtered by the kidneys. The normal rate for humans is 125mL/min or 180L/day. The fluid that is filtered (and not reabsorbed later) is excreted as urine.
Define glomerular filtration rate Name and describe the pressures which are effective at the glomerulus under normal conditions and result in glomerular filtration?
Glomerular filtration is a passive process in which hydrostatic pressure forces fluids and solutes through a membraneThe glomerular filtration rate (GFR) is directly proportional to the net filtration pressure and is about 125 ml/min (180 L/day).The glomeruli function as filters. High glomerular blood pressure (55 mm Hg) occurs because the glomeruli are fed and drained by arterioles, and the afferent arterioles are larger in diameter than the efferent arterioles.
