Your kidneys are two small organs that do some very big jobs. They clean your blood by removing waste, balance important minerals like salt and potassium, and help control your blood pressure.
These organs work all day and night to keep you healthy, even though you might not notice it.
Because your kidneys are so important, it’s a good idea to check how well they are working from time to time. Doctors use kidney function tests to do this. These tests are simple and can help find kidney problems early—sometimes before you feel anything is wrong.
One common test is called the Blood Urea Nitrogen test, or BUN for short. Your body makes urea when it breaks down protein in food. Normally, your kidneys remove this waste through urine.
But if your kidneys aren’t doing their job well, urea builds up in your blood. The BUN test checks how much of this waste is in your blood. A normal BUN level is between 7 and 20 mg/dL, though the exact range can vary.
Another important test is the Serum Creatinine test. Creatinine is a waste product made by your muscles. Healthy kidneys remove creatinine from the blood. If your kidneys are not working properly, the creatinine level goes up. For men, normal levels are between 0.6 and 1.2 mg/dL. For women, they are slightly lower, between 0.5 and 1.1 mg/dL.
To get a better idea of overall kidney health, doctors use a calculation called the Glomerular Filtration Rate, or GFR. This number is based on your creatinine level, age, gender, and body size. It shows how well your kidneys are filtering blood.
A GFR of 60 or higher is normal. If it falls below 60, it may mean you have kidney disease. If it goes down to 15 or less, it could be a sign of kidney failure.
Urine tests are also helpful for checking kidney health. A Urinalysis looks at how your urine looks and what’s in it. If your urine has protein or blood in it, that could be a sign of kidney problems.
Another urine test is the Albumin-to-Creatinine Ratio (ACR), which checks how much of a protein called albumin is in your urine. Even small amounts can be an early sign of kidney damage.
People with diabetes, high blood pressure, or a family history of kidney problems should be especially careful. Kidney problems can happen quietly without symptoms, so regular testing is very important.
It’s also worth noting that one unusual test result doesn’t always mean something serious. Things like diet or dehydration can affect results. But if your results are not in the normal range, your doctor might repeat the test or do more checks to be sure.
In short, kidney function tests are a smart and easy way to keep an eye on your health. They help catch problems early so you and your doctor can take action before things get worse. If you’re at risk or just want to be safe, talk to your doctor about getting tested.
If you care about kidney health, please read studies about how to protect your kidneys from diabetes, and drinking coffee could help reduce risk of kidney injury.
For more information about kidney health, please see recent studies about foods that may prevent recurrence of kidney stones, and eating nuts linked to lower risk of chronic kidney disease and death.
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