Kidney Function
Creatinine, eGFR, and BUN: key kidney markers.
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Included Markers
3 markersA kidney function panel measuring Creatinine, eGFR, and Urea (BUN). These markers reflect how well the kidneys are filtering waste products from the blood.
Why this test?
The kidneys filter waste products from the blood, regulate fluid balance, and help control blood pressure. Changes in kidney function can develop gradually and may not cause symptoms until they are more advanced. Measuring kidney markers can provide early data about how the kidneys are performing.
Who is this test for?
This test may be relevant for women who:
- Want to check kidney function as part of a health assessment
- Take medications that may affect the kidneys
- Have a family history of kidney disease
- Experience symptoms such as changes in urination, swelling, or fatigue
What is tested?
This panel measures three markers:
- Creatinine: a waste product from muscle metabolism; elevated levels may suggest reduced kidney filtration
- eGFR (Estimated Glomerular Filtration Rate): a calculated value that estimates how well the kidneys are filtering; based on creatinine, age, and sex
- Urea (BUN): a waste product from protein metabolism; levels may rise when kidney function is reduced
What can this test tell you?
Creatinine and eGFR together provide an estimate of kidney filtration capacity. A reduced eGFR may suggest that the kidneys are not filtering as efficiently. Elevated urea may reflect increased protein breakdown or reduced kidney clearance. These markers are typically interpreted together and in the context of hydration, diet, and medication use.
How is the sample collected?
The test requires a blood draw at a certified sample point (afnamepunt). There are over 750 locations across the Netherlands. After placing your order, you can select a convenient location and schedule your visit.
When is this test useful?
This test may be considered when:
- You want to assess kidney function as part of a routine check
- You take medications that may affect the kidneys
- You have risk factors for kidney disease
- You want baseline kidney data for future comparison
What do the results mean?
Each marker is shown with your value and the reference range. A normal eGFR generally suggests the kidneys are filtering adequately. A reduced eGFR or elevated creatinine may warrant further investigation. Temporary factors such as dehydration or high protein intake can affect results, so interpretation should be done by a healthcare provider.
Preparation
No specific preparation is needed. Staying well hydrated the day before can help ensure accurate results. No fasting is required.
What happens after the results?
Your results are typically available within a few working days. Each marker is shown with your value, the reference range, and an explanation. These results can be discussed with your healthcare provider to determine whether any follow-up may be appropriate.
From order to report in 4 steps
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Receive your lab referral
Within 2-3 hours you'll receive an email from ZorgDomein with a barcode. Orders outside business hours are processed the next business day.
Get tested at a lab near you
Show the barcode on your phone and bring a valid ID. Done in under 15 minutes.
Receive your report from the doctor
A BIG-registered physician reviews your hormone values and writes a personal report. On your dashboard within a few business days.
Choose your hormone test
Browse our hormone panels and pick what you want tested. Compare markers and prices, or build a custom test.
Receive your lab referral
Within 2-3 hours you'll receive an email from ZorgDomein with a barcode. Orders outside business hours are processed the next business day.
Get tested at a lab near you
Show the barcode on your phone and bring a valid ID. Done in under 15 minutes.
Receive your report from the doctor
A BIG-registered physician reviews your hormone values and writes a personal report. On your dashboard within a few business days.
Always a location near you
With more than 450+ certified phlebotomy points across the Netherlands.
What We Test
This test includes 3 biomarkers to give you a comprehensive health picture.
BUN (blood urea nitrogen) measures the amount of urea nitrogen in your blood, a waste product formed when the body breaks down protein. It is primarily used to evaluate kidney function and can be influenced by diet, hydration status, and liver health.
Learn moreCreatinine is a waste product of creatine, a substance your muscles use for energy supply. The kidneys filter creatinine from your blood and excrete it through urine. When the kidneys function less well, creatinine accumulates in the blood. The creatinine level is therefore one of the most important markers for assessing kidney function. It is often measured alongside eGFR, which gives a more precise estimate of how well your kidneys are working.
Learn moreThe eGFR (estimated glomerular filtration rate) estimates how much blood your kidneys filter per minute. It is calculated from your creatinine level, age, sex, and ethnicity using the CKD-EPI formula. eGFR is more accurate than creatinine alone and is used to classify kidney function loss into stages. An eGFR above 90 ml/min is normal; below 60 ml/min indicates clinically relevant kidney function reduction.
Learn moreUrea (BUN)
KidneyBUN (blood urea nitrogen) measures the amount of urea nitrogen in your blood, a waste product formed when the body breaks down protein. It is primarily used to evaluate kidney function and can be influenced by diet, hydration status, and liver health.
BUN is a valuable marker for assessing how effectively your kidneys are filtering waste from your blood. Elevated levels may indicate that the kidneys are not functioning optimally, which can be associated with dehydration, kidney disease, or other underlying conditions. Monitoring BUN alongside other kidney markers such as creatinine and eGFR provides a more comprehensive picture of renal health and helps detect potential problems early.
Creatinine
KidneyCreatinine is a waste product of creatine, a substance your muscles use for energy supply. The kidneys filter creatinine from your blood and excrete it through urine. When the kidneys function less well, creatinine accumulates in the blood. The creatinine level is therefore one of the most important markers for assessing kidney function. It is often measured alongside eGFR, which gives a more precise estimate of how well your kidneys are working.
Chronic kidney damage often progresses silently and rarely causes symptoms in early stages. Your kidneys can lose up to 50% of their function before you notice anything. Creatinine and eGFR are the standard markers for early detection. In diabetes and high blood pressure — the two leading causes of chronic kidney damage — periodic creatinine monitoring is part of clinical guidelines. Kidney function monitoring is also recommended during long-term use of NSAIDs (painkillers such as ibuprofen and diclofenac), ACE inhibitors, or certain antibiotics. An elevated creatinine does not always indicate kidney damage. In people with high muscle mass (strength athletes) or high protein intake, the value can naturally be higher. Conversely, low creatinine in the elderly or in people with little muscle mass can mask reduced kidney function — eGFR is more reliable in those cases.
eGFR (Estimated Glomerular Filtration Rate)
KidneyThe eGFR (estimated glomerular filtration rate) estimates how much blood your kidneys filter per minute. It is calculated from your creatinine level, age, sex, and ethnicity using the CKD-EPI formula. eGFR is more accurate than creatinine alone and is used to classify kidney function loss into stages. An eGFR above 90 ml/min is normal; below 60 ml/min indicates clinically relevant kidney function reduction.
Chronic kidney damage is largely irreversible, but progression can be slowed or stopped if detected early. eGFR is the cornerstone of that early detection. Diabetes and high blood pressure together account for more than 60% of all cases of chronic kidney damage — periodic eGFR monitoring in these patient groups is therefore essential. At an eGFR below 60 ml/min, medication adjustments are often needed because many drugs are excreted by the kidneys. The dosage of contrast agents for CT scans must also be adjusted.
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