Also Known As
Kidney Panel
Kidney Function Panel
Renal function tests
Kidney function tests
Formal Name
Renal Function Panel/tests
This article was last reviewed on
This article waslast modified on 20 October 2021.
At a Glance
Why Get Tested?

To help diagnose and manage conditions affecting kidney (renal) 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.

When To Get Tested?

When you have signs and symptoms that suggest that you may have a condition affecting the function of your kidneys; when you are being treated for kidney disease; when you have certain risk factors for kidney disease, such as high blood pressure or diabetes.

Sample Required?

A blood sample taken from a vein in your arm

Test Preparation Needed?

You may be instructed to fast for 8-12 hours (no food, only water) prior to the test, but this is rare.

On average it takes 7 working days for the blood test results to come back from the hospital, depending on the exact tests requested. Some specialist test results may take longer, if samples have to be sent to a reference (specialist) laboratory. The X-ray & scan results may take longer. If you are registered to use the online services of your local practice, you may be able to access your results online. Your GP practice will be able to provide specific details.

If the doctor wants to see you about the result(s), you will be offered an appointment. If you are concerned about your test results, you will need to arrange an appointment with your doctor so that all relevant information including age, ethnicity, health history, signs and symptoms, laboratory and other procedures (radiology, endoscopy, etc.), can be considered.

Lab Tests Online-UK is an educational website designed to provide patients and carers with information on laboratory tests used in medical care. We are not a laboratory and are unable to comment on an individual's health and treatment.

Reference ranges are dependent on many factors, including patient age, sex, sample population, and test method, and numeric test results can have different meanings in different laboratories.

For these reasons, you will not find reference ranges for the majority of tests described on this web site. The lab report containing your test results should include the relevant reference range for your test(s). Please consult your doctor or the laboratory that performed the test(s) to obtain the reference range if you do not have the lab report.

For more information on reference ranges, please read Reference Ranges and What They Mean.

What is being tested?

A renal panel is a group of tests that may be performed together to evaluate kidney (renal) function. The tests measure the amounts 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 about 170 litres of blood a day, removing waste products that form from the metabolism (breakdown) 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 the amounts of necessary chemicals in the body including potassium, sodium, calcium, phosphorus, chloride, and bicarbonate (TCO2) 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 concentrations.

If the kidneys are not functioning properly, waste products can accumulate in the blood and the amount of fluid 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:

Blood Tests

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:

Minerals

  • 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.

Protein

  • 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.

Waste products

  • Urea– 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.

Sugar

  • 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.
  • HbA1c – is a longer term marker of sugar levels, particularly useful in establishing if diabetes mellitus is present and, if it is, how well it is controlled.

Two calculated values may also be reported with a renal panel:

  • 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 concentrations in the blood; the formula takes into account the person's age, gender (sex), 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.

Urine Tests

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.

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Common Questions
  • 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.

  • When is it requested?

    A healthcare professional may request 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 healthcare professional may request a renal panel when someone has signs and symptoms of kidney disease. Although 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-coloured
    • 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 requested at regular intervals when someone is being treated for kidney disease for monitoring purposes, or is on medications that can affect the kidney or are secreted by the kidneys. It can also be measured in generally ill patients to determine if the kidneys are affected, how much water has been lost and whether some medications can be given (those that can affect or are secreted by the kidneys).

  • 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 results 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 summarises what results might mean in relation to kidney disease or dysfunction.

    Test Association with kidney disease/dysfunction
    Electrolytes: Sodium, Potassium, Chloride, Bicarbonate Concentrations of electrolytes in the blood can be affected by kidney disease in different ways depending on the cause, with some concentrations 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 (low bicarbonate) or hyperkalaemia (high potassium) may result.
    Phosphorus High blood concentrations are associated with kidney disease.
    Calcium Low blood concentrations may be seen with kidney failure, and sometimes very high.
    Albumin A low blood concentrations may indicate that the kidneys cannot prevent albumin from leaking into the urine and being lost (can be called nephrotic syndrome).
    Urea High results suggest 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 concentrations can suggest impaired kidney function due to conditions listed above for urea.
    Glucose/HbA1c High blood concentrations indicates diabetes, a common cause of kidney disease.
    Cystatin C A high serum cystatin C result indicates a low GFR (glomerular filtration rate).
    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?

    Additional testing may be performed, such as kidney imaging or a kidney biopsy, if blood and urine testing indicate the possibility of kidney disease. For more information on imaging and other types of testing, see the article on Kidney Disease.

  • 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.. The usual minimum ‘renal profile’ consists of sodium, potassium, creatinine and eGFR.

  • What other tests might be ordered to assess kidney function?

    NICE (National Institute for Health & Care Excellence) guideline (NG203) published August 2021 recommend two tests, in addition to blood pressure measurement, to screen for and/or monitor 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 reviews 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 professional 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, examination findings, and medical and family history.

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