Kidney Function

The kidneys filter blood continuously, removing waste products and excess fluid. Changes in kidney filtration can develop gradually and may not produce noticeable symptoms until function has declined significantly. Measuring creatinine, eGFR, and urea together provides a practical overview of how well the kidneys are performing their filtration role.

This test may be relevant for:

• People who want to check their kidney health as part of a general wellness check
• Those with a family history of kidney conditions
• Anyone taking medications that may affect kidney function
• People with conditions such as high blood pressure or diabetes, which may influence kidney health over time
• Those who have had previously abnormal kidney values and want to follow up

This panel includes three kidney-related markers:

• Creatinine: a waste product from normal muscle metabolism, filtered by the kidneys. Elevated levels may suggest reduced filtration.
• eGFR (estimated Glomerular Filtration Rate): calculated from creatinine and other factors, it estimates how efficiently the kidneys are filtering. A lower eGFR may indicate reduced kidney function.
• Urea (BUN): a waste product from protein metabolism, also filtered by the kidneys. Levels can be influenced by diet, hydration, and kidney function.

Elevated creatinine combined with a reduced eGFR may suggest that the kidneys are not filtering as efficiently as expected. Urea provides additional context, as it can be affected by protein intake and hydration as well as kidney function. Together, these three markers give a clearer picture than any one of them alone.

A single set of results is a snapshot. Values can fluctuate based on hydration, diet, and physical activity. A healthcare provider can help determine whether your results indicate a trend or a temporary variation.

This test uses a blood sample collected at a certified sample point (afnamepunt). With over 750 partner locations across the Netherlands, you can select a location that suits you. A trained phlebotomist performs the blood draw, and results are typically available within a few working days.

This test may be useful when:

• You want a focused check on kidney filtration without a full metabolic panel
• You are taking medications that can affect kidney function, such as certain pain relievers or blood pressure medications
• You have a condition that may influence kidney health over time
• You want to establish a baseline for future comparison

Each marker is shown with your value and the reference range. An eGFR above 90 is generally considered normal. Values between 60 and 89 may or may not indicate an issue, depending on other factors. An eGFR below 60 on repeated testing may suggest reduced kidney function that warrants further evaluation.

Your report includes explanations for each marker. We recommend discussing the results with a healthcare provider, especially if values fall outside the expected range or if you have risk factors for kidney conditions.

No specific preparation is needed for this test. Staying well hydrated before your appointment may make the blood draw more comfortable and can help ensure accurate results, as dehydration may temporarily affect creatinine levels.

Your results are typically available within a few working days. The report includes your values with reference ranges and clear explanations. If any value falls outside the expected range, this is highlighted. We recommend reviewing the results with a healthcare provider, who can interpret them alongside your medical history and advise on any follow-up steps.