Kidney function test for your kidney values

Your kidneys play a role in filtering waste products from your blood and keeping your fluid balance in check. A kidney function test brings your creatinine, your eGFR and your urea together in one overview.

For active people, this can be interesting, because a high protein intake, supplements and heavy training can all play a part in these values. By measuring them, you can build a picture of where your kidney values stand.

This way you work with data instead of assumptions, which fits an approach where you want to understand and optimise your body.

A kidney function test may suit people who want insight into their kidney values. It can be relevant for:

• Athletes and active people with a high protein intake who want to follow their kidney values
• People who use supplements such as creatine and want insight into their creatinine and eGFR
• People who had deviating kidney values before and want to keep following them
• People who want to keep an eye on their kidney values periodically
• People who want to combine this basic panel with a broader blood test later

This panel measures three blood values around your kidney function:

• Creatinine is a waste product that your kidneys filter from your blood.
• eGFR is an estimate of how well your kidneys filter, based on your creatinine.
• Urea is a waste product that can say something about your kidney function and your protein metabolism.

Together these values give you a view of your kidney function.

The results can show you how your kidney values compare to the reference ranges. Your eGFR gains context alongside your creatinine, because it is calculated from it, while your urea is often looked at as well.

For active people, it is worth knowing that a high muscle mass or a creatine supplement can influence your creatinine. Keep in mind that a single value is not a diagnosis: your kidney values only gain meaning in combination with your situation and your history.

For this blood test, a staff member draws a small tube of blood at a certified location. You can choose from more than 750 collection sites in the Netherlands, so there is almost always a location near you.

You need little for this, apart from your appointment confirmation and a valid ID. The draw itself usually takes only a few minutes.

A kidney function test can be useful at different moments. Some people choose to test:

• When they have a high protein intake and want insight into their kidney values
• When they use supplements such as creatine and want to follow their creatinine
• When their kidney values were deviating before and they want to keep following them
• When they want to keep an eye on their kidney values periodically
• When they want to start with a basic panel before expanding

What the results mean depends on your personal situation. Each value is compared to a reference range, but a value outside that range does not automatically mean something is wrong.

With a kidney panel, a doctor often looks at your creatinine, your eGFR and your urea together, and also considers factors such as your muscle mass. Always discuss any deviating values with your GP, so you know what the results may mean for you personally.

For a kidney function test, you usually do not need to fast. Drink enough water on the day of the draw, as your hydration can influence your values.

If you trained intensively shortly before the draw or took a creatine supplement, keep that in mind, as it can temporarily affect your creatinine. If in doubt, you can discuss your situation with your GP.

You receive your results digitally in your account, usually within a few working days. For each value, you can see whether it falls within the reference range. You can then share your results with your own GP.

Every blood test result includes a professional assessment from a BIG-registered doctor. For treatment decisions, discuss your results with your GP.