Importance of Routine Blood Tests to Check Your Kidney Function
Blood Tests for Kidney Function

If you want to know whether your kidney is in good working condition, it usually involves a blood test for checking your kidney function that measures how much urea, certain dissolved salt, and creatinine are present.
The kidney is an important organ in the body whose function is to filter the blood – taking out impurities that may be harmful to your general health.
What is urea?
When protein breaks down, it forms a waste product called urea. And this is usually removed from the body via urine.
Should there be a high level of urea in the blood – a condition called uraemia, it implies that the kidneys are not effective in function, or you don’t have sufficient water in the body – dehydration. This is one of the things the doctor looks out for in a blood test for kidney function.
What is creatinine?
The muscles produce a waste product known as creatinine. From the point of production, creatinine gets into the bloodstream and typically leaves the body via urine.
Having a high level of creatinine in the blood is a sign of a dysfunctional kidney.
There is a more precise diagnosis of kidney function with creatinine measurement than urea. Here, the effect of muscle mass is considered.
A great amount of muscle and little fat in the body equals a higher creatinine level. But a little muscle and plenty of fat in the body produces a low level of creatinine.
Estimated glomerular filtration rate (eGFR)
This gives an idea of how well or how bad your kidneys are working. Creatinine levels in the blood may prove very precise in detecting kidney function, but eGFR is a far more accurate method.
Do you know that the eGFR can be estimated using creatinine level in the blood? This is possible using race, sex, and age.
Sometimes, this calculation is done with a computer’s aid, and the result comes out along with the creatinine blood test.
The eGFR has a normal value that ranges between 90 to 120ml/min. If the value of the eGFR is less than 60ml/min, it is interpreted as certain damage has happened to the kidney. This means that the lower the level of eFGR, the more severe the damage to the kidney.
Dissolved salts
Again, in the test for kidney function, some dissolved salts are routinely measured. These include:
- Potassium
- Bicarbonate
- Chloride
- Sodium
Often, these salts are described as electrolytes.
If any of these salts’ blood level is unusual, it may be a result of an issue in the kidney.
It is important to bear in mind that other health conditions can impact salt balance in the blood.
So, to be sure what exactly is causing damage to your kidney, visit a good clinic to book a blood test for kidney function. But should everyone have this test? Answering this viral question brings us to the next section of this article.
Who should undergo this kidney function test?
Before we go into that, let it be known that routine kidney examination via a blood test is a very common medical test.
This blood test may be performed:
- As an inclusion in an overall health check
- Should you have experienced dehydration that makes your body water level low and increases urea
- Should you feel your kidney is damaged and cannot function well.
Like we said earlier, if the level of urea and creatinine in the body is high, the less functional your kidney becomes.
When the seriousness of a kidney failure needs to be measured, it is the creatinine level in the blood that is used to achieve this.
Kindly note that creatinine is not dangerous; however, when the amount in the blood is high, it is a red flag for kidney failure.
Consequently, many other waste products will remain inside the body; they will not be cleared.
Usually, your doctor will recommend that you get treated alongside a dialysis should the blood creatinine levels increase to pass a designated value.
- Before and after starting treatment with some medications, there are certain medications whose side effect is kidney damage! Based on this, the function of your kidney is examined pre and post-treatment with some medicines. It is also important you don’t self-medicate. Always consult your doctor before you take any drug for any health issue. You may not know if the impact of the medicine will be detrimental to your kidney health.
Are there other tests to check for kidney function?
In general, what diagnoses the health of your kidney is the routine kidney blood test. Your doctor can explain more about this test during a consultation. It is highly important for your health.
Should the blood test result come out as abnormal, it means the root cause of the kidney damage cannot be determined.
Should this be the case, you may need to take other tests to properly diagnose what is causing the problem in your kidney.
The doctor may recommend:
- Other blood tests
- Kidney biopsy
- Urine tests
- X-rays
- Scans
Key takeaways
The surest way to know if you are having a kidney problem is by taking a blood test for kidney function.
Certain substances in the blood are measured during this test to determine how severe the damage is.
The creatinine blood level is more accurate than urea measurement yet less precise than the estimated glomerular filtration rate (eGFR).
A low level of certain salts in the blood can also contribute to kidney problem, but it may also be due to other underlying health issues. Consult your doctor for accurate diagnostic testing.
Do not play with the health of your kidney. As much as possible, eat the right food that will promote the kidney’s well-being and always go for routine medical checkup. A severe kidney problem may cause serious complications to health.