What is included in a renal function test (renal panel)?
A renal panel is a number of individual lab tests that are grouped together as they give valuable information about the kidneys, ureters (the structures that carry urine), and bladder. Together these structures are known as the “renal system,” and are responsible for controlling the balance of fluid and electrolytes in the body. The tests that are always included in a renal panel are:
- Sodium, potassium, and chloride: These are the basic electrolytes; they are regulated by the kidney, and failure of this regulation or failure of the kidney itself will be seen as a change in these levels.
- Phosphorus and calcium: While technically electrolytes, these are commonly called minerals. They are regulated by the hormones in the body and the intestines. The kidneys still play a role in their regulation.
- Creatinine (Cr) and blood urea nitrogen (BUN): The Cr and BUN are the best markers of kidney function. The Cr is one of the first things to increase if the kidneys are damaged. The BUN level can be compared to the Cr level to give more information about what is causing damage to the kidneys.
- Albumin: Albumin is a basic protein found in the blood. If the kidneys are damaged, this protein is able to seep out into the urine, decreasing its levels in the body. A low blood albumin combined with a high urine albumin level indicates that protein is being lost into the urine.
Do you need to fast before a renal panel?
No, you do not need to fast before a renal panel. Drinking abnormally large amounts of water or other fluids may cause small changes in the values. Follow your normal daily diet before getting a renal panel.
Why would a doctor order a renal panel?
There are many reasons why a doctor would order a renal panel. They are a part of the routine labs that are performed as part of a physical examination and may also be used to diagnose and monitor illness. The most common conditions that are monitored/diagnosed using a renal panel are:
- High blood pressure
- Kidney failure
- Diabetes
- Autoimmune diseases
- Intestinal diseases
- Infections
- The effects of medications on your body
What are the signs that something is wrong with your kidneys?
The kidneys control the balance of fluid and electrolytes in your body. Damage to the kidneys is typically slow and leads to vague symptoms. The most common symptoms are:
- Weakness and fatigue
- Loss of appetite
- Nausea and vomiting
- Elevated blood pressure
- Swelling of the extremities
- Decreased urine output
The vague nature of these symptoms is the reason why renal panels are critical for the diagnosis of renal failure. Sudden and severe injury to the kidneys is very rare but often presents with a total loss of urine production. This finding is not present in chronic kidney failure until the most severe stages of the disease.
What is a normal renal function panel?
A renal function panel is a set of lab tests. A normal renal function panel is one that has all of the lab values in question within a normal range. There are often small abnormalities in individual tests, even in healthy individuals. The pattern of abnormal tests and the severity of these abnormalities is more important than any one abnormal value.
How long does it take to get the results of a kidney panel?
It can take anywhere between one hour and 2-3 days to get the results of a renal function panel. This time is determined by where the test is performed. If the test is done in an emergency room, it takes about an hour. If done at a lab center or a primary care doctor's office, it may take multiple hours or multiple days. This is because the tests are run on slower machines or grouped together with many other tests.
What is the best indicator of kidney failure?
The best indicator of kidney failure is the serum creatinine, which is commonly abbreviated Cr. Creatinine is a waste product that the renal system normally filters out. If the renal system is damaged in any way, creatinine will begin to accumulate in the blood. The other tests in the renal function panel can help to determine the cause of this lost filtering ability as well as monitor any other effects renal failure may be having on the body.
