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Kidney Function Tests

Kidney Function Tests

Kidney Function Tests are also known as Renal Function Tests or  U&Es (Urea & Electrolytes)

The reason for measuring these parameters is because the kidney function corelates well with the levels of Urea and Electrolytes in blood tests. They routinely used to monitor the body’s electrolyte balance and give a clear picture about the good kidney function.

Urea & Electrolytes

From £39 – *Turnaround time:  4-6 Hours

  • Sodium (Na+)
  • Potassium (K+)
  • Urea
  • Creatinine
  • eGFR

The kidney Function Tests are also included in many of general health and wellness profiles.

Blood measurements of urea gives information about acute pathology of kidneys and creatinine is a marker indicate shorter or longerterm renal dysfunction.

The levels of electrolytes in the blood are utmost important and need to be tightly controlled, because high levels of potassium (hyperkalaemia) is a risk-factor for heart attacks and arrhythmias. Similarly, very low sodium can cause confusion, and loss of consciousness.

The kidney function blood tests are highly recommended for anyone with high blood pressure, diabetes, or a family history of kidney disease.


Moreover, is important to have regular kidney function test to monitor people that taking long-term medications cleared by the kidneys (by glomerular filtration), to ensure that such medications are not causing renal damage. 

The most common medications secreted by the kidneys include are diuretics (thiazide diuretics) another blood pressure medications such as ACE-inhibitors.



Common signs that indicate Kidney Problems

The initial way to identify kidney problems, that indicate that a blood test should be consider, are symptoms and signs. 

  • Frequent urges to urinate (pass urine).
  • High blood pressure
  • The presence of blood in the urine
  • Difficultly when you want to begin urination.
  • Pains during urination
  • The retention (build-up) of fluids in the body which causes the hands and feet to swell.


The above symptoms usually indicate kidney problems when persist or occur simultaneously.

If these symptoms are present, we will then proceed to carry out the kidney function tests, which will reveal the reason for the symptoms.



This test is what helps us check for blood and proteins present in the urine. We know that there are many factors like heavy physical workout and the rest, which may influence the presence of proteins in the urine. This is why we do not mind running this test over and over again to get your accurate result. We may ask you to give us a 24-hour sample of urine collection. This will help us know the rate at which creatinine (a waste product of the breakdown of muscle tissue) is clearing form your body.


Serum Creatinine Test

This is a blood test which helps us determine if there is a creatinine buildup in your blood. On normal occasion, the kidney should completely filter out this waste product, so its presence at a high level in your blood tells us that there is a problem with your kidney. The National Kidney Foundation says if the creatinine level in the blood of men is higher than 1.2 milligrams per decilitre (mg/dL) and 1.4 mg/dL for men signifies a kidney problem.


Blood Urea Nitrogen (BUN)

We use this blood test to determine the amount of waste product in your blood. The BUN tests show how much nitrogen (the product of the breakdown of protein) is present in the blood.

The reason we like the BUN tests is that it tells us about the supplements or medications you have regularly been taking. With the intrusion of drugs in the BUN, we advise you to stop some drugs for some days before coming for the test.

The normal BUN level ranges from 7-20 mg/dL and a value higher than these rings a bell in our ears that you could be suffering from a serious health problem and that we should do something to help you. It is worthy of notice that kidney damage is not the only reason for an elevated level of BUN.


Estimated GFR

We carry out this test to know the efficiency of your kidneys in the filtration of wastes. This test works by considering different factors like the test result (mostly the level of creatinine), the gender, age, race, weight and height.

If this test produces a result that is less than 60 ml/minute/1.73m2, then it may be that you have kidney disease.



Sodium is an essential electrolyte involved in several bodily functions. The kidneys regulate its level in the body. High or low levels can be seen in a number of diseases, and the level can be influenced either way by prescribed medication (eg diuretics can cause a drop-in sodium).



Potassium is another essential electrolyte, whose level in the blood is largely determined by the kidneys. Like sodium, screening for low or high levels of potassium can indicate a problem with health due to disease or inappropriate medication. Potassium levels are very sensitive to storage – if there is any delay in testing, the level is often higher than would otherwise be expected. Normally, it is readily apparent if the rise is due to storage change as other test results will usually be normal.



Urea, like creatinine, is a waste product of normal bodily function – its level in the blood is controlled entirely by the kidneys. Rising levels of Urea that are detected in your pathology results may indicate kidney disease or damage, although small rises may also be a sign of dehydration. Low levels are of no concern.



Creatinine, like urea, is a waste product of bodily processes. The kidneys control its elimination from the blood. A rise in creatinine within a health screening, especially if urea levels are also high, will usually mean there is a degree of compromise of the kidneys. Small rises can be a sign of dehydration. Low levels are of no concern.


This test requires you to fast for at least eight hours before your blood is drawn.


Abnormal results may indicate kidney disease, diabetes, or hormone imbalances.


Your doctor will perform follow-up tests to diagnose any of these conditions.


TAT is referred to working days Monday – Friday. Gold Medical Centre  doesn’t hold any responsibility as this depends on laboratory services, (check our T&C)

Make an appointment

      020 32 31 5000 

    Department Hours

    Tuesday - Friday09:00 - 18:00
    Saturday9:00 - 16:00

    Contact Centre Hours

    Tuesday – Saturday9am – 16:00pm
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