Are your kidneys healthy? Know your numbers to find out
March is National Kidney Month, so it’s the perfect time to get informed and be proactive about your kidney health. One in three Americans are at risk for chronic kidney disease, and most kidney damage is irreversible. Many people don't experience symptoms of chronic kidney disease, so it's important to get screened, know your numbers and prevent future renal failure.
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Are your kidneys healthy? Know your numbers to find out.
March is National Kidney Month, which makes it the perfect time to get familiar with your kidney health if you're not already.
One in three Americans are at risk for kidney disease, and it can affect anyone at any time. The best way to treat kidney disease and prevent lasting damage is to catch it early, so being aware of your kidney health and checking on it regularly is important.
The good news is, assessing your kidney health is simple. There are just two non-invasive tests you need to take to evaluate your kidneys, and those two resulting numbers become your barometer. Being proactive about your kidney health is all about knowing your numbers and how they compare to what is considered healthy.
What do my kidneys do again?
Kidneys are two bean-shaped organs about the size of an adult fist, located on either side of your spine below the rib cage.
Your kidneys are critically important and do many jobs for your body, including filtering waste out of your blood. They also control the production of red blood cells, release hormones that regulate blood pressure, and make vitamins that control growth.
Blood enters your kidney through an artery from the heart, then it travels through millions of tiny blood filters, separating the waste from the blood. The newly cleaned blood is pumped back into the bloodstream via the veins, while the waste is stored as urine in the bladder. Your kidneys filter about 200 quarts of fluid every 24 hours. Needless to say, your kidneys are vital to your well-being. You can, however, function healthily with just one kidney, which makes kidney donations possible.
What are kidney numbers?
The two numbers you'll need to become familiar with to assess your kidney health are your albumin to creatinine ratio (ACR) and your estimated glomerular filtration rate (eGFR). We'll refer to these as your "kidney numbers."
The ACR measures how much of the protein albumin is present in your urine. (Creatinine refers to a waste product filtered out of the blood by the kidneys.) This protein is not bad; your body needs it. But it should be in your blood, not your urine. If too much of it is present, that could indicate one or both of your kidneys are not functioning properly. Your ACR can be assessed through a simple urine sample.
The eGFR measures the amount of creatinine in your blood, then plugs that number into a formula that takes into account your age, gender, and body size. The resulting number is your eGFR. As you may remember, creatinine is a waste product that should be in the urine, not the blood, if your kidneys are functioning properly. With a simple finger prick blood test, a doctor can evaluate the amount of creatinine in your blood and estimate your GFR.
Note: Your actual GFR number is more complicated to determine and requires experienced personnel, so it is typically only performed in research settings and transplant centers. The eGFR is recommended as a sufficient measure of kidney health (alongside the ACR) by the National Kidney Foundation. The eGFR is typically a reliable indicator of kidney health but in some cases could be inaccurate and require further testing, particularly if you have had a limb amputated, are malnourished, or highly obese.
What are considered "normal" kidney numbers?
For ACR, a healthy range is under 30 (mg/mmol). This represents a normal to "mildly increased" level of albumin (classified as A1). A moderately increased level is 30-300 (classified as A2) while over 300 indicates a severely increased level of albumin (classified as A3).
For eGFR, a healthy number is considered over 90 (ml/min/1.73m2). If you have an eGFR from 60-90, you may have stage G1 or G2 of chronic kidney disease (CKD). If it falls between 30-59, the number indicates stage G3; and less than 30 indicates stages G4-G5, which are the most severe. An eGFR of 15 or lower indicates renal failure.
By cross-referencing these two numbers, your doctor can evaluate whether or not you have CKD, what stage you're in, and what your treatment plan should be.
What if my numbers are not normal?
If your numbers are not in the "normal" or "healthy" range, your doctor will work with you to come up with a treatment plan. There is no cure for chronic kidney disease (damage to your kidneys is usually permanent), but you can prevent further damage, particularly if you are in the early stages. Much of the prevention efforts will include changes to diet and lifestyle, like avoiding excess salts and proteins, exercising, quitting smoking, and controlling your blood pressure.
If you are in the later stage of kidney disease, you may have to undergo dialysis, which helps your kidney filter the blood when it cannot do it on its own. In the case of renal failure, a transplant may be needed.
What causes chronic kidney disease?
The primary risk factors for chronic kidney disease are diabetes and high blood pressure. Others include heart disease, a family history of kidney disease, being over 60, and even being African-American, Hispanic, Native American, or Asian.
What's the difference between chronic kidney disease and acute kidney disease?
Chronic kidney disease is more common and develops slowly over time. Many people with chronic kidney disease do not even realize they have it, particularly in the earlier stages, so it's important to be familiar with your numbers. If you have symptoms, they might include itching, muscle cramps, fatigue, too much urine or not enough, foamy urine, blood in your urine, swelling, nausea or vomiting, trouble catching your breath, or trouble sleeping.
Acute kidney disease comes on suddenly and often has noticeable symptoms like back pain, nausea, diarrhea, or fever. In some cases, it can be reversed. If you are having these symptoms, contact your doctor right away.
When should I get screened?
If you are over the age of 40, you should get screened for kidney disease as well as liver disease and C-reactive protein (this indicates inflammation, which many studies have linked to cardiovascular disease).
If you are over the age of 20 and exhibit any risk factors, you should also get screened, or if you simply want to be informed about your health. Life Line Screening's kidney function test can give you a detailed look at your health as well as peace of mind with a simple finger-prick blood test.
The Bottom Line
About 1 in 3 Americans are at risk for chronic kidney disease, and once the damage has been done, it's typically irreversible. Unfortunately, many people don't experience symptoms of chronic kidney disease until it's already progressed into moderate or severe stages. By doing a simple screening and knowing your kidney numbers — your ACR and eGFR — you can be informed about your health and prevent future kidney failure.
Schedule a screening today to discover what your numbers are and be proactive about your kidney health!
National Kidney Foundation - "Know Your Numbers: Two Simple Tests"
National Kidney Foundation - "10 Signs You May Have Kidney Disease"
American Kidney Fund - "Chronic Kidney Disease"
Lab Tests Online - "eGFR"
National Kidney Foundation - "ACR"