Renal function test is done to evaluate kidney function and in the diagnosis of kidney diseases. There are several reasons for which your doctor will ask for a renal function test. They can also be done to monitor the progression of renal insufficiency. The BUN-to-creatinine ratio of a Renal function test may aid in the evaluation of a person’s state of hydration.
Symptoms that may indicate a problem with your kidneys include:
- High blood pressure.
- Blood in the urine.
- Frequent urges to urinate,
difficulty beginning urination,
- Swelling of the hands and feet due to a buildup of fluids in the body.
A single symptom may not mean something serious. However, when occurring simultaneously, these symptoms suggest that your kidneys aren’t working properly. Renal function tests can help determine the reason.
Types of Renal Function Test
A urinalysis screens for the presence of protein and blood in the urine. There are many possible reasons for protein in your urine, not all of which are related to disease. Infection increases urine protein, but so does a heavy physical workout. Your doctor may want to repeat this test after a few weeks to see if the results are similar.
Your doctor may also ask you to provide a 24-hour urine collection sample. This can help doctors see how fast a waste product called creatinine is clearing from your body. Creatinine is a breakdown product of muscle tissue.
Serum creatinine test
This blood test examines whether creatinine is building up in your blood. The kidneys usually completely filter creatinine from the blood. A high level of creatinine suggests a kidney problem. According to the National Kidney Foundation (NKF) , a creatinine level higher than 1.2 milligrams/deciliter (mg/dL) for women and 1.4 mg/dL for men is a sign of a kidney problem.
Blood urea nitrogen (BUN)
The blood urea nitrogen (BUN) test also checks for waste products in your blood. BUN tests measure the amount of nitrogen in the blood. Urea nitrogen is a breakdown product of protein. However, not all elevated BUN tests are due to kidney damage.
Common medications, including large doses of aspirin and some types of antibiotics, can also increase your BUN. It’s important to tell your doctor about any medications or supplements that you take regularly. You may need to stop certain drugs for a few days before the test. A normal BUN level is between 7 and 20 mg/dL. A higher value could suggest several different health problems.
This test estimates how well your kidneys are filtering waste. The test determines the rate by looking at factors, such as: test results, specifically creatinine levels, age, gender, race, height weight. Any result lower than 60 milliliters/minute may be a warning sign of kidney disease.
How The Tests Are Performed
Kidney function tests usually require a 24-hour urine sample and a blood test. A 24-hour urine sample is a creatinine clearance test. It gives your doctor an idea of how much creatinine your body expels over a single day. On the day that you start the test, you urinate into the toilet as you normally would when you wake up.
For the rest of the day and night, you are to urinate into a special container provided by your doctor. Keep the container capped and refrigerated during the collection process. Make sure to label the container clearly and to tell other family members why it’s in the refrigerator.
On the morning of the second day, urinate into the container when you get up. This completes the 24-hour collection process. Follow your doctor’s instructions about where to drop the sample off. You may need to return it either to your doctor’s office or a laboratory.
BUN and serum creatinine tests require blood samples taken in a lab or doctor’s office. The technician drawing the blood first ties an elastic band around your upper arm. This makes the veins stand out. The technician then cleans the area over the vein. They slip a hollow needle through your skin and into the vein.
The blood will flow back into a test tube that will be sent for analysis. You may feel a sharp pinch or prick when the needle enters your arm. The technician will place gauze and a bandage over the puncture site after the test. The area around the puncture may develop a bruise over the next few days. However, you shouldn’t feel severe or long-term pain.
Results and Treatment
Your doctor will focus on treating the underlying condition if the tests show early kidney disease. Your doctor will prescribe medications to control blood pressure if the tests indicate hypertension . They’ll also suggest lifestyle and dietary modifications.
If you have diabetes, your doctor may want you to see an endocrinologist. This type of doctor specializes in metabolic diseases and can help ensure that you have the best blood glucose control possible.
If there are other causes of your abnormal kidney function tests, such as kidney stones and excessive use of painkillers, your doctor will take appropriate measures to manage those disorders. Abnormal test results mean you’ll probably need regular kidney function tests in the months ahead. These will help your doctor keep an eye on your condition.
Ways To Keep Your Kidney Healthy
Hydrate, but don’t overdo it. “Contrary to popular belief, no studies have proven over-hydration as an effective practice in enhancing kidney function,” says nephrologist James Simon, MD. So, while it’s always a good idea to drink enough water, drinking more than the typical four to six glasses a day probably won’t help your kidneys do their job any better.
Eat healthy foods. Your kidneys can tolerate a wide range of dietary habits, but Dr. Simon points out that most kidney problems arise out of other medical conditions like high blood pressure and diabetes. Because of this, he suggests you follow healthy, moderate eating habits to control weight and blood pressure. Preventing diabetes and high blood pressure will help keep kidneys in good condition.
If you’re healthy, getting your exercise is a good idea because, like healthy eating habits, regular physical activity can stave off weight gain and high blood pressure. But do be mindful of how much exercise you do, especially if you’re not conditioned.“Overexerting yourself when you’re not fit and healthy can put a strain on your kidneys, especially if you exercise so much that you cause excessive breakdown of muscle tissue.”
Use caution with supplements and herbal remedies. Excessive amounts of certain vitamin supplements and some herbal extracts may be harmful to your kidneys. Talk to your doctor about any vitamins and herbs you plan to take.
Smoking can damage blood vessels, which decreases the flow of blood in the kidneys. When the kidneys don’t have adequate blood flow, they can’t function at optimal levels. Smoking also increases the risk of high blood pressure as well as the risk of kidney cancer.
Don’t overdo it when taking over-the-counter medications. “Common non-prescription pills like ibuprofen and naproxen (NSAID’s) can cause kidney damage if taken too regularly over a prolonged period. If you’re at risk, get regular kidney function screening. If you have either diabetes or high blood pressure, your physician should screen for kidney dysfunction as part of routine care for those conditions.
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