Normal Kidney Function GFR

(Glomerular Filtration Rate)

What is GFR?

Our kidneys filter our blood by removing extra water and wastes to make urine. The glomerular filtration rate (GFR) shows how efficiently the kidneys are filtering. It is estimated that 10% of the total world population is affected by chronic kidney diseases (CDK) and millions of people die each year because they do have access to affordable treatment. When kidney diseases are diagnosed at an early stage, people can take necessary steps to prevent their kidneys.

Other names of GFR

 Glomerular filtration rate, Estimated GFR, eGFR.

 

How Do Doctors Compute GFR?

Doctors generally compute your GFR by taking a blood sample. Then they apply a mathematical formula that determines how effectively your kidneys are removing waste.

 

A person can not find his GFR on his own because he may need specific or precise data from a blood test.

 

The mathematical formula generally  includes following:

• Age

• Sex

• Weight

• Height

• Measurement of  creatinine (waste product that is filtered by the kidneys) present in blood

• Ethnicity

 

What Is GFR in a Blood Test?

Glomeruli are tiny filters that are present in the kidneys. They filter waste from our blood. Damage to these glomeruli can cause kidney disease.

 

Doctors use the result of a blood test in a mathematical formula that estimates how perfectly the glomeruli are working.

 

Before blood test, you should:

• Stop taking over-the-counter (OCD) drugs or prescribed medications

• Fast (not drink or eat)

• Avoid foods like cola, dried fruits, processed meats, bananas, etc

 

Your doctor generally tells you how to prepare yourself for the blood test.

 

How will the Test Feel?

When the needle goes in to draw blood, some individuals feel slight pain. Others may feel only a scratching sensation or prick. The technician places dry cotton to the test site. Afterwards, the test site develops a bruise over the next few days. However, this soon went away.

 

Why do I need a GFR Test?

The GFR test evaluates how effectively your kidneys are filtering your blood. Your doctor generally orders this test if there are some signs that your kidneys are not performing well. It may also be done to determine the progress of kidney disease.

 

Doctors recommend this test to people having chronic kidney disease. It is also recommended to persons who develop kidney disease due to:

• Diabetes

• Heart disease

• High blood pressure

• Family history of kidney disease

• Frequent urinary tract infections

• Urinary blockage

What Is a Normal GFR?

If you have a kidney disease, then you may want to become familiar with your GFR.

 

Age is the main factor in determining GFR. Older people generally have lower GFR than normal, because GFR decreases with age.

 

But no matter what your age is. Your GFR lies between following:

• GFR of 90 or aboveis in normal range

• GFR of 60 -89 means early stage kidney disease

• GFR of 15 -59indicates kidney disease

• GFR below 15means a kidney failure

 

What is a normal GFR for my age?

You may wonder what is a normal GFR of a 70-year old person. Age is the main factor in determining GFR. Old people have low levels of GFR even if they do not have kidney disease, because it decreases with age.

 

Following table provides more accurate information of GFR regarding age.

 

Age (Years)	GFR
20-29	116
30-39	107
40-49	99
50-59	93
60-69	85
Above 70	75

 

What does a GFR 120 mean?

 A GFR value of 120 is considered normal. Normal GFR ranges from 90-120mL/min/1.73 m2.

 

What Does a Low GFR Mean?

A lower GFR means your kidneys are unable to filter your blood as they should.

 

A GFR level below 60 is a sign of chronic kidney disease. If your GFR is under 15, that means you have kidney failure and you may need dialysis or a kidney transplant.

 

Causes of low GFR

A decrease in GFR is due to:

• Underlying kidney disease

• Volumeloss

• Dehydration

 

Kidney function level chart according to GFR

Stage of CDK	Average GFR	What does it means	Kidney function
1	90 or above	Mild kidney damage Normal kidney function	90-100%
2	60-89	Kidney damage with slight loss of kidney function	60-89%
3a	45-59	Moderately reduced kidney function	45-59%
3b	30-44	Severely reduced kidney function	30-44%
4	15-29	Very severe or end-stage kidney failure	15-29%

 

Risks of GFR test

There are some risks involved in taking blood samples. Arteries and veins in size from one individual to another and from one part of the body to another. Taking blood samples from a few people may be more difficult than other people.

 

Other risks that are associated with withdrawing blood sample includes following:

• Excessive bleeding

• Feeling lightheaded or fainting

• Multiple punctures to find veins

• Hematoma (blood accumulation under skin)

• Infection (occur when skin is broken)

 

Can I Improve My GFR?

GFR can be improved by changing lifestyle. You should keep in mind that there is no cure for chronic kidney diseases but you can improve your kidney kidney functioning by adopting healthy habits.

 

Because high blood pressure and diabetes are the major causes of CKD, it’s necessary to keep their level under control.

 

Other tips to improve your kidney health are:

• Avoid processed foods, that have high salt contents

• Take a low-salt diet. Talk to your physician about DASH diet.

• Eat plenty of vegetables and fruits.

• Limit your protein intake because too much proteincan constrain kidneys to remove protein wastes.

• Exercise regularly.

• Quit or cut back on smoking.

• Maintain a healthy weight according to your age, sex and height.