Your kidneys work quietly in the background every day, doing some of the most important jobs in your body.
These two bean-shaped organs filter your blood, remove waste and extra fluid, help control your blood pressure, and keep the levels of key minerals like sodium and potassium in balance.
Because your kidneys are so important, it’s a good idea to keep track of how well they’re working. That’s where kidney function tests come in.
Kidney function tests are simple medical tests that help doctors check if your kidneys are doing their job properly. These tests can show early signs of kidney trouble, often before you notice any symptoms. That’s why they’re often included in routine check-ups, especially for people who may be at higher risk of kidney disease.
One common test is the Blood Urea Nitrogen (BUN) test. Urea is a waste product your body makes when it breaks down protein from the food you eat. Your kidneys remove this waste through your urine. If your kidneys aren’t working well, urea can build up in your blood.
The BUN test measures how much urea nitrogen is in your blood. A normal result is usually between 7 and 20 milligrams per deciliter (mg/dL), but this can vary based on your age and the lab doing the test.
Another important test is the Serum Creatinine test. Creatinine is another waste product made by your muscles as they work.
Healthy kidneys remove creatinine from the blood. If your kidneys aren’t doing this properly, creatinine levels rise. Normal creatinine levels are around 0.6 to 1.2 mg/dL for men and 0.5 to 1.1 mg/dL for women. People with more muscle may have slightly higher levels.
To get an overall picture of kidney health, doctors often calculate something called the Glomerular Filtration Rate (GFR). This is not a direct test but a formula based on your creatinine levels, age, sex, and body size.
It estimates how much blood your kidneys are filtering each minute. A GFR of 60 or more is usually considered normal. A number below 60 could mean kidney disease. If it falls to 15 or lower, it may mean your kidneys are close to failing.
Urine tests also help check kidney function. A basic test called a urinalysis looks at how your urine looks and what’s in it. It can find things like protein or blood, which aren’t supposed to be there. Protein in the urine, for example, may mean your kidneys’ filters are damaged.
There’s also the Albumin-to-Creatinine Ratio (ACR) test. This checks how much of a protein called albumin is in your urine compared to creatinine. Even small amounts of albumin can be an early warning sign of kidney damage, especially in people with diabetes or high blood pressure.
If you have diabetes, high blood pressure, or a family history of kidney problems, these tests are especially important. You might not feel any symptoms when your kidneys start having problems, which is why regular testing can help catch issues early and give you more time to act.
It’s also important to remember that one unusual test result doesn’t always mean you have a serious problem. Things like how much water you drank or what you ate before the test can affect the results. But if a test shows something unusual, your doctor may want to repeat it or order more tests.
In short, kidney function tests are a smart way to keep an eye on your health. They help find problems early, give you and your doctor valuable information, and help you take steps to protect your kidneys and your overall well-being.
If you care about kidney health, please read studies about pesticide linked to chronic kidney disease, and this drug may prevent kidney failure in people with diabetes.
For more health information, please see recent studies about drug duo that may treat kidney failure, and results showing these vegetables may protect against kidney damage.
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