To help diagnose and manage conditions affecting kidney function; may be used as part of general health screening or to screen someone who is at risk of developing kidney disease, or to follow someone with known kidney disease
A blood sample drawn from a vein in your arm
You may be instructed to fast for 8-12 hours (no food, only water) prior to the test.
A renal panel is a group of tests that may be performed together to evaluate kidney (renal) function. The tests measure levels of various substances, including several minerals, electrolytes, proteins, and glucose (sugar), in the blood to determine the current status of the kidneys.
The kidneys are a pair of bean-shaped organs that are located at the bottom of the ribcage in the right and left sides of the back. They normally filter nearly 150 quarts of blood a day, removing waste products that form from the metabolism of food and from normal cell activity. The kidneys form urine to expel excess water from the body together with these waste products that are removed from the blood.
The kidneys help regulate pH and levels of necessary chemicals in the body—including potassium, sodium, calcium, phosphorus, chloride, and bicarbonate (CO2)—by separating them out from the waste materials and releasing them back into the blood, getting rid of only as much or as little as needed to maintain normal blood levels.
If the kidneys are not functioning properly, waste products can accumulate in the blood and fluid levels can increase to dangerous levels, causing damage to the body or a potentially life-threatening situation. Numerous conditions and diseases can result in damage to the kidneys. The most common causes of and main risk factors for kidney disease are diabetes and hypertension. For more on the types and causes, see the article on Kidney Disease.
The individual tests included in a renal panel can vary by laboratory, but the tests typically performed include:
Electrolytes – electrically charged chemicals that are vital to normal body processes, such as nerve and muscle function; among other things, they help regulate the amount of fluid in the body and maintain the acid-base balance. Electrolytes include:
- Phosphorus – a mineral that is vital for energy production, muscle and nerve function, and bone growth; it also plays an important role as a buffer, helping to maintain the body's acid-base balance.
- Calcium – one of the most important minerals in the body; it essential for the proper functioning of muscles, nerves, and the heart and is required in blood clotting and in the formation of bones.
- Albumin – a protein that makes up about 60% of protein in the blood and has many roles such as keeping fluid from leaking out of blood vessels and transporting hormones, vitamins, drugs, and ions like calcium throughout the body.
- Urea/ Blood Urea Nitrogen (BUN) – urea is a nitrogen-containing waste product that forms from the metabolism of protein; it is released by the liver into the blood and is carried to the kidneys, where it is filtered out of the blood and eliminated in the urine.
- Creatinine – another waste product that is produced by the body's muscles; almost all creatinine is eliminated by the kidneys.
- Glucose – energy source for the body; a steady supply must be available for use, and a relatively constant level of glucose must be maintained in the blood.
Three calculated values may also be reported with a renal panel:
- Urea (BUN)/creatinine ratio – a comparison of urea (nitrogen) to creatinine content in the blood
- Estimated Glomerular Filtration Rate (eGFR) – a calculated estimate of the actual glomerular filtration rate (GFR, the amount of blood filtered by the glomeruli in the kidneys per minute) derived from creatinine levels in the blood; the formula takes into account the person's age, gender, race, and sometimes height and weight.
- Anion gap -- anion gap (AG or AGAP) is a value calculated using the results of an electrolyte panel. It evaluates the difference between measured and unmeasured electrical particles (ions or electrolytes) in the fluid portion of the blood.
How is the sample collected for testing?
A blood sample is drawn from a vein in the arm.
Is any test preparation needed to ensure the quality of the sample?
Fasting for 8-12 hours (no food, only water) before sample collection may be required.
How is it used?
A renal panel may be used to evaluate kidney function, to help diagnose kidney-related disorders, to screen those who may be at risk of developing kidney disease or to monitor someone who has been diagnosed with kidney disease.
The individual tests that make up a renal panel can vary depending on the laboratory that performs the testing, but a panel may include:
- Electrolytes: sodium, potassium, chloride, bicarbonate (CO2)
- Blood Urea Nitrogen (BUN)
Click on the links above for more about these individual tests.
Three calculated values may also be reported with a renal panel:
There are other laboratory tests that can be used to assess kidney function, including a urinalysis, urine protein or creatinine clearance. For those with diabetes or high blood pressure (hypertension), a urine albumin (microalbumin) test, which measures small amounts of albumin leakage from the blood into the urine, may also be used to detect early kidney damage. When both albumin and creatinine are measured in a random urine sample, an albumin/creatinine ratio (ACR) can be calculated. This may be done to more accurately determine how much albumin is escaping from the kidneys into the urine.
When is it ordered?
A health practitioner may order a renal panel when someone has risk factors for kidney dysfunction such as high blood pressure (hypertension), diabetes, cardiovascular disease, obesity, elevated cholesterol, or a family history of kidney disease.
A health practitioner may order a renal panel when someone has signs and symptoms of kidney disease, though early kidney disease often does not cause any noticeable symptoms. It may be initially detected through routine blood or urine testing. Examples of some signs and symptoms include:
- Swelling or puffiness, especially around the eyes or in the face, wrists, stomach, thighs or ankles
- Urine that is foamy, bloody, or coffee-colored
- A decrease in the amount of urine
- Problems urinating, such as a burning feeling or abnormal discharge during urination, or a change in the frequency of urination, especially at night
- Mid-back pain, below the ribs, near where the kidneys are located
A renal panel may also be ordered at regular intervals when someone is being treated for kidney disease for monitoring purposes.
What does the test result mean?
Renal panel test results are not diagnostic but rather indicate that there may be a problem with the kidneys and that further testing is required to make a diagnosis and determine the cause. Results of the panel are usually considered together, rather than separately. Individual test result can be abnormal due to causes other than kidney disease, but taken together with risks and/or signs and symptoms, they may give an indication of whether kidney disease is present.
The following table summarizes what results might mean in relation to kidney disease or dysfunction.
Test Association with kidney disease/dysfunction Electrolytes: Sodium, Potassium, Chloride, Bicarbonate Electrolyte blood levels can be affected by kidney disease in different ways depending on the cause, with some levels decreasing while others increase. In general, kidney dysfunction or disease can cause an imbalance among the electrolytes. When these positively and negatively charged ions are out of balance, it can affect the fluid balance and/or pH of the blood. As kidney dysfunction worsens, complications such as metabolic acidosis may result. Phosphorus High blood level is associated with kidney disease. Calcium Low blood level may be seen with kidney failure. Albumin A low blood level may indicate that the kidneys cannot prevent albumin from leaking into the urine and being lost. Urea/BUN High level suggests impaired kidney function caused by acute or chronic kidney disease, damage, or failure, or due to another condition causing decreased blood flow to the kidneys, such as CHF or dehydration, or causing obstruction of urine flow, such as prostate disease or kidney stones. Creatinine High blood level suggests impaired kidney function due to conditions listed above for urea. Glucose High blood level indicates diabetes, a common cause of kidney disease. Urea (BUN)/Creatinine ratio High ratio may be due to a condition such as decreased blood flow to the kidneys while low ratio may be due to other conditions such as liver disease. eGFR Calculated from the blood creatinine test result; an eGFR below 60 mL/min suggests that some kidney damage has occurred; an eGFR below 15 indicates kidney failure (see table in the eGFR article) Anion gap A high result can indicate excess acid (acidosis) in the blood that may be related to kidney disease, but the acidosis can also be caused by many other conditions.
Is there anything else I should know?
Will these tests always be run as a panel?
No, each test that is usually included in a renal panel may be run independently or along with different tests, depending on the purpose of the testing. For example, the electrolytes (sodium, potassium, chloride, and bicarbonate) may be run as an electrolyte panel as part of a routine health screen or to detect a potential problem with someone's fluid or acid-base balance, which could be caused by heart disease, for example. The glucose test is also commonly performed to screen for, diagnose, and monitor diabetes.
What other tests might be ordered to assess kidney function?
The National Kidney Foundation (NKF) and the National Kidney Disease Education Program (NKEDP) recommend two tests, in addition to blood pressure measurement, to screen for kidney disease: urine protein (either urine albumin, urinalysis or urine total protein) and estimated glomerular filtration rate (eGFR). When a structural problem is suspected, a variety of imaging tests can be used to evaluate the kidneys. A sample of kidney tissue, a biopsy, is sometimes helpful in diagnosing the specific cause of the problem. For more information, see the article on Kidney Disease.
Can I have kidney disease if I feel fine?
Yes. Kidney disease often does not cause noticeable symptoms until late in the disease. That is why it is important, especially for those with risk factors for kidney disease, to have regular health exams so that any disorders or diseases that may affect the kidneys can be promptly addressed.
Can I have abnormal test results and not have kidney disease?
Yes. Since the tests included in the renal panel can have broad applications, abnormal results on one or more of the tests could indicate a problem other than kidney disease. Your healthcare provider will interpret the results of your renal panel tests by looking at all of your results, along with the results of any other tests you had performed as well as your symptoms, exam findings, and medical and family history.
On This Site
Tests: Albumin, BUN, Bicarbonate, Calcium, Chloride, Creatinine, Creatinine Clearance, Cystatin C, eGFR, Glucose, Phosphorus, Potassium, Sodium, Urine Albumin and Albumin/Creatinine Ratio, Beta-2 Microglobulin, Basic Metabolic Panel, Comprehensive Metabolic Panel, Complete Blood Count, Urinalysis, Urine Protein
Elsewhere On The Web
National Kidney and Urologic Diseases Information Clearinghouse
National Kidney Disease Education Program: Learn About Kidney Disease
American Association of Kidney Patients: Chronic Kidney Disease
National Kidney Foundation
American Kidney Fund: Free Screening Locations