How to Judge Kidney Function

An important way to stay on top of your kidney functioning is to visit the doctor for the appropriate testing. Kidney-functioning tests will give your doctor a sense of whether your kidneys are doing their job. Tests will show if you are in the early stages of kidney failure. This how-to test will give you the basic steps you will need to set up and understand your kidney-functioning test.

Instructions

Getting the Test

• 1

  Set up an appointment to visit your doctor. Inform your doctor that you want to receive blood work to evaluate your kidney functioning.

• 2

  Ask your doctor if you need to fast before your test. The most common test of kidney functioning is the blood urea nitrogen test. BUN tests do not require fasting. However, doctors will often want to conduct other tests, such as a complete blood-count test. Many of these other tests will require you to fast for 12 hours.

• 3

  Visit your doctor or the appropriate testing lab on the day of your test.

• 4

  Provide your arm to the nurse for blood extraction. The nurse will take a vial or two of blood from your arm with a needle.

• 5

  Wait for the results of your BUN test. Your doctor will probably indicate whether the results suggest normal kidney functioning. However, as long as you have your BUN number, you can analyze the results yourself. According to the Mayo Clinic, as long as your BUN is between 7 and 20 milligrams per deciliter (mg/dl) you are in the normal range. Any results above 50 mg/dl are considered high and warrant further investigation. A high BUN reading may indicate you have impaired kidney functioning. However, other factors, such as dehydration or a high-protein diet, may lead to high BUN. Therefore, a high reading will warrant additional blood and/or urine tests. Your doctor will attempt to control any of the other variables that may raise BUN levels.