Symptoms and diagnosis
The DaVita.com GFR Calculator
Having chronic kidney disease (CKD) means that kidneys are not working at their full capacity. Usually when kidney disease is chronic, kidneys are slowly losing their ability to work effectively.
Fortunately, kidneys can do a pretty good job, even when they're not functioning at 100 percent. Also, there are steps that can often be taken to try to keep kidneys working as long as possible and delay dialysis.
Because kidney function decreases over time, kidney disease has been divided into five stages. When someone is diagnosed with chronic kidney disease, the next step is to determine the stage of the disease. The National Kidney Foundation (NKF) has published additional information on the stages of kidney disease.
How to determine stage of chronic kidney disease
Kidney function is measured by how well the kidneys clean the blood. The glomerular filtration rate (GFR) is a good way to find out the patient's stage of kidney disease. The main factor in estimating the GFR is finding out the level of creatinine in the blood. Your doctor will order blood tests that will list your serum creatinine. This is a waste product that comes from muscle activity. When kidneys are functioning, they remove creatinine from the blood. As kidney function slows, blood levels of creatinine rise.
A mathematical equation is used to estimate the GFR. In addition to serum creatinine, other factors in the equation include age, race and gender. Sometimes, optional factors such as weight, blood urea nitrogen (BUN) and serum albumin are used to get the patient's GFR level. Once the GFR level is known the stage can be determined. See the chart below for the stages:
| Stage | GFR Level | Description |
|---|---|---|
| Stage 1 | 90 mL/min or more | Healthy kidneys or kidney damage with normal or high GFR |
| Stage 2 | 60 to 89 mL/min | Kidney damage and mild decrease in GFR |
| Stage 3 | 30 to 59 mL/min | Moderate decrease in GFR |
| Stage 4 | 15 to 29 mL/min | Severe decrease in GFR |
| Stage 5 |
Less than 15 mL/min or on dialysis |
Kidney failure |
What do the stages mean?
As CKD progresses a patient may develop other problems including high blood pressure, anemia, malnutrition, bone disease and problems with the nervous system. Knowing the accurate GFR level helps doctors provide the proper treatment and medication dosages at each stage.
In Stage 1 and Stage 2 CKD, there are often few symptoms. Early CKD is usually diagnosed if there are other problems present such as:
- High blood pressure
- Higher than normal levels of creatinine or urea in the blood
- Blood or protein in the urine
- Evidence of kidney damage in an MRI, CT scan, ultrasound, or contrast X-ray
- A family history of polycystic kidney disease
Since diabetes and high blood pressure are the top two causes of chronic kidney disease, these diseases must also be controlled. Managing blood sugar and blood pressure, plus taking prescribed blood pressure medication and limiting protein are recommended to help slow the progression of CKD.
In Stage 3 CKD, anemia (a shortage of red blood cells) and/or early bone disease may appear and should be treated to reduce problems down the road. As Stage 3 progresses, the National Kidney Foundation recommends the patient see a nephrologist—a doctor who specializes in treating kidney disease.
When CKD has progressed to Stage 4, it is time to begin preparing for dialysis and/or a kidney transplant . The patient should discuss the two types of dialysis—hemodialysis and peritoneal dialysis—with the doctor to determine which is best. If the patient will undergo hemodialysis, a fistula or graft vascular access can be put in to give it time to mature before dialysis begins. A catheter also needs to be put in place for peritoneal dialysis.
By Stage 5 CKD the kidneys can no longer clean the blood, so dialysis or a kidney transplant is needed for survival.
How to find out the GFR
Use DaVita's GFR Calculator to figure out aGFR. This calculator uses the formula for adults only. It will ask you to provide:
| Information requested | Reason for asking |
|---|---|
| Age | GFR decreases with age and disease. |
| Serum creatinine | Measures waste product in blood that comes from muscle activity. The kidneys usually remove creatinine. When kidney function slows, creatinine rises. This result can be obtained from the blood work ordered by a doctor. |
| Gender | Medical literature states that men usually have more muscle mass than women, so the calculation is adjusted based on gender. |
| Race | Medical literature states that blacks usually have more muscle mass than other ethnicities, so the calculation is adjusted based on race. |
After submitting information, the GFR Calculator will tell you an estimated GFR level. Always consult a physician for more information about medical conditions.
The earlier kidney disease is detected, the better the chance of slowing or stopping its progression. The DaVita GFR Calculator was designed to help you learn about the stages of kidney disease and provide information about typical steps taken to ensure the best care. See your physician to get a diagnosis of chronic kidney disease and determine your stage.
Disclaimer: This is not designed to be a self-diagnostic tool. When using this GFR Calculator, you should not assume That you have or do not have CKD until your doctor has diagnosed you. GFR estimates may not be reliable in certain individuals. There are other factors besides chronic kidney disease that will increase GFR such as, muscle trauma, vigorous exercise, unusually high or low muscle mass (such as in athletes or malnourished individuals), unusually high or low dietary creatine (such as in those taking creatine supplements or vegetarians) and possibly other conditions. It is important that you talk to your doctor if you have any concerns about your kidney function or the results from using this calculator.
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