Purpose of the test

The purpose of a renal panel test is to find or rule out potential kidney impairment or disease. Depending on the circumstances, it may be used for diagnosis, screening, or monitoring.

Diagnosis is the identification of a health problem after signs or symptoms have started. A renal panel may be ordered if the doctor believes that symptoms could be related to an issue affecting the kidneys.

Screening is testing with the goal of early detection of a problem. Screening tests are done before any symptoms have occurred. For people who are at higher risk of developing kidney disease, a renal panel may be prescribed to try to reveal problems at an earlier stage.

Monitoring is how a patient’s situation can be tracked over time. Repeat testing with a renal panel can show if the condition of the kidneys is getting better or worse. This monitoring may be done after treatment for kidney disease. It can also be used to watch for changes to kidney function when taking medications that can cause kidney impairment.

What does the test measure?

A renal panel includes multiple measurements. However, not all renal panel tests are exactly the same. The components can depend on the laboratory or the measurements requested by the doctor prescribing the test.

The most common components tested in most renal panels include:

• Glucose: Also known as blood sugar, glucose provides energy for the body. Excess glucose in the blood, though, can be a sign of metabolic problems like diabetes.
• Phosphorus: Phosphorus is an essential mineral for your bones, teeth, nervous system, and muscles. Phosphorus comes primarily from the foods and drinks that you consume.
• Calcium: Calcium is a mineral that is vital for the bones, muscles, cardiovascular system, and nervous system. The main source of calcium is your diet, and the body stores calcium in the bones.
• Potassium: Potassium is a type of electrolyte. Electrolytes are minerals that enable acid-base balance, healthy fluid levels, and proper functioning of muscles and nerves. Potassium comes from your diet and is found throughout the body.
• Sodium: Sodium is another electrolyte that comes from your diet, and the amount of sodium in the body is largely controlled by the kidneys.
• Chloride: Chloride is an electrolyte that works in conjunction with other electrolytes to carry out various functions, including preserving a healthy balance of fluids.
• Bicarbonate: Bicarbonate is another electrolyte. Levels of bicarbonate help assess the amount of carbon dioxide (CO2) in your blood.
• Albumin: Albumin is a protein that is produced in the liver and found in the blood. It carries important substances through the body and helps maintain the proper pressure in the blood vessels so that fluids do not leak out of the blood.
• Creatinine: Creatinine is a waste byproduct that is consistently formed as a result of normal muscle activity. The kidneys remove creatinine from the blood so that it can be carried out of the body in urine.
• Blood urea nitrogen (BUN): Urea nitrogen, sometimes just called urea, is a waste product from protein activity. Like creatinine, it is removed from the blood by the kidneys and cleared from the body in urine.

Other measurements that may also include in a renal panel include:

• Anion gap: The anion gap is a comparison of different electrolytes. Specific electrolytes can be positively or negatively charged, and this test assesses the balance between the two types. This measurement helps determine if you have too much or too little acid in your blood.
• Estimated glomerular filtration rate (eGFR): The eGFR is an evaluation of kidney function. Glomeruli are tiny filters in the kidneys, and the eGFR is a calculation of how much blood they are filtering every minute. There are different ways to calculate eGFR, but most tests use a special formula based on your creatinine level.
• Total protein: There are several kinds of proteins that can be found in the blood, and total protein is a count of all of them. These proteins include albumin and multiple types of globulins, which are made by the immune system.
• BUN-to-creatinine ratio: In some cases, comparing the amounts of the waste products BUN and creatinine can provide information about whether abnormal levels are being caused by problems in the kidneys or another part of the body.

When should I get a renal panel test?

A renal panel test can be used in a range of circumstances, and the doctor may include specific measurements depending on your situation. As a diagnostic test, a renal panel is most frequently used when you have symptoms that could be explained by a kidney problem. Examples of symptoms that can be tied to kidney impairment or disease include:

• Urinary changes including changes to the frequency, quantity, or appearance of your urine
• Unexplained swelling, especially in your arms, hands, legs, and/or face
• Itching
• Loss of concentration
• Appetite changes
• Difficulty breathing
• Nausea and/or vomiting
• Fatigue
• Muscle cramps or pain

A test like the renal panel may also be used for diagnosis when you have general symptoms without a clear cause or are being evaluated in urgent care or emergency setting.

As a screening test, the renal panel or other tests of kidney health are most often prescribed if you have certain risk factors for kidney disease. Some of these risk factors include high blood pressure, diabetes, and a family history of kidney disease.

For people with an elevated risk of kidney problems, screening with a renal panel may be part of normal health checkups. Screening of this type is not standard in people who do not have risk factors.

A renal panel can be used as a monitoring test if you have had kidney problems in the past or have already had an abnormal renal panel test. If you are receiving treatment for kidney injury or disease, a renal panel may be used to gauge your response to that therapy.

If you are going to have a medical procedure or take any drugs that can impair kidney function, your doctor may prescribe a renal panel before and/or after to monitor for possible kidney-related side effects.

How to get tested

In general, a renal panel is ordered by a doctor, and the blood sample is drawn in a medical office, laboratory, or hospital.

Before the test

• For many renal panel tests, you will need to fast for 8 to 12 hours before your blood draw.
• During this time, you can only drink water. You cannot eat any food or drink other beverages.
• However, because the exact components of a renal panel test can vary, you should ask your doctor about whether you need to fast beforehand.
• You should also tell your doctor about any prescriptions, over-the-counter medications, or supplements that you take.
• If any of these can affect the test, your doctor may ask you to temporarily stop taking them before the test.

During the test

• When it’s time for your test, you will be seated while a technician or nurse prepares to draw your blood.
• They will tie a band around your upper arm to enhance blood flow lower in your arm.
• An antiseptic wipe will be used to clean the skin around your vein, and then a needle will be inserted into the vein.
• The needle is used to withdraw a vial of blood and is then removed from your arm.
• This type of blood draw is a routine procedure that normally lasts only a few minutes.
• You may experience some brief pain or a stinging sensation during the test.

After the test

• When the needle is removed from your arm, a bandage or cotton swab will be used to stop any further bleeding.
• You may experience some soreness or bruising, but these effects are rarely long-lasting.
• If you are required to fast, you may want to bring a snack immediately after the test.
• Once your blood draw is finished, you can return to most normal activities, including driving.