Creatinine (fingerstick)
Measure your kidney function at home with creatinine finger prick including eGFR and CKD-EPI calculation.
Fingerstick at home – no collection point needed
How it works
- 01
Receive your fingerstick kit
You receive a fingerstick kit with clear instructions
- 02
Prick & collect
Easily collect a few drops of blood yourself
- 03
Mail back
Return via medical mail to the lab
What is Creatinine?
Creatinine is a waste product that results from the normal breakdown of muscle tissue. It is transported through the bloodstream to the kidneys, where it is filtered and excreted through urine. Creatinine is an important biomarker for kidney function.
What is eGFR and CKD-EPI?
The eGFR (estimated Glomerular Filtration Rate) is a calculation that provides an estimate of how well your kidneys are functioning. It is calculated using the CKD-EPI formula (Chronic Kidney Disease Epidemiology Collaboration), the most accurate and current formula for estimating kidney function.
The CKD-EPI formula uses:
- Your creatinine value
- Age
- Gender
The eGFR indicates how much blood (in milliliters) your kidneys can filter per minute per 1.73m² body surface area. This provides a much more accurate picture of kidney function than creatinine alone.
Why would you test Creatinine and eGFR?
Testing creatinine and calculating eGFR is essential for assessing kidney function. This combination provides the most complete picture of how well your kidneys are working. The test is used for:
- Routine check-ups and preventive screening
- Suspected kidney disease
- Monitoring known kidney diseases
- Assessment of medication dosing (many medications are excreted through the kidneys)
- Evaluation of risk factors such as diabetes and high blood pressure
- Screening for family history of kidney disease
What does it indicate?
The eGFR is the primary indicator of kidney function and is classified into different stages:
- ≥90 mL/min/1.73m²: Normal to excellent kidney function (stage 1)
- 60-89 mL/min/1.73m²: Mildly decreased kidney function (stage 2)
- 45-59 mL/min/1.73m²: Moderately decreased kidney function (stage 3a)
- 30-44 mL/min/1.73m²: Moderately to severely decreased kidney function (stage 3b)
- 15-29 mL/min/1.73m²: Severely decreased kidney function (stage 4)
- <15 mL/min/1.73m²: Kidney failure, dialysis may be needed (stage 5)
What does elevated Creatinine / low eGFR mean?
Elevated creatinine and low eGFR indicate decreased kidney function. The kidneys are less able to effectively filter waste products from the blood. Possible causes include:
- Chronic kidney disease (most common)
- Acute kidney injury
- Dehydration (temporary)
- Diabetes or high blood pressure (damage kidneys over time)
- Nephrotoxic medications (NSAIDs, certain antibiotics)
- Kidney stones or urinary tract obstruction
- Very high muscle mass or intense training (can temporarily raise creatinine)
What does low Creatinine / high eGFR mean?
Low creatinine is less common and may indicate:
- Decreased muscle mass due to age, illness, or malnutrition
- Severe liver disease (reduced creatine production)
- Pregnancy (physiologically decreased)
A very high eGFR (>120 mL/min/1.73m²) is often normal in young, healthy people. It can also occur with hyperfiltration in early-stage diabetes, where the kidneys temporarily work harder.
Preparation
For the most reliable results, it is recommended to:
- Fast for 8-12 hours before the test
- Avoid heavy physical exercise 24 hours before the test
- Be well hydrated
Strong scientific evidence
This test is included in Dutch healthcare guidelines and is regularly used for its respective indications.
Rationale for this test
Creatinine en eGFR (berekend met CKD-EPI formule) zijn standaard-bepalingen in Nederlandse zorgrichtlijnen voor het beoordelen van nierfunctie. De NHG-Standaard Chronische nierschade beschrijft creatininemeting via vingerprik als gevalideerde methode, en de CKD-EPI formule is de aanbevolen berekeningswijze voor eGFR. Deze test heeft een goed onderbouwde klinische betekenis voor screening, monitoring en diagnostiek van nierziekten.
Sources consulted
Dutch clinical guidelines and healthcare organisations
Independent information sources
We recommend consulting these independent sources before ordering a preventive health check.
- Client brochure PGO (NVvPG, September 2023)
Brochure on preventive health checks: careful choice, reliability, pros and cons, checklist.
- RIVM — Health tests
Independent information about preventive health checks from the National Institute for Public Health and the Environment.
- Thuisarts.nl
Reliable patient information about illnesses and complaints from Dutch GPs (NHG).
- Allesovertesten.nl (NVKC)
Public-facing website of the Dutch Society for Clinical Chemistry with explanations of blood tests and laboratory values.
Frequently asked questions
Answers to what people usually want to know.
See fingerstick instructionsFull instructions with visual guidanceHow does the fingerstick test work from A to Z?
After ordering we ship the collection kit to your home. You prick your fingertip, collect a few drops of blood, return it in the envelope, and receive your result digitally by email.
How do I collect my blood sample?
A small prick on your fingertip lets you collect a few drops into a tube. The instructions include step-by-step photos and video, so no guessing required.
When and how do I receive my result?
Usually 2 to 5 working days after the lab receives your sample. You get an email with a link to your digital result, including explanation per value.
What if the collection doesn't work?
Some people find the fingerstick tricky at first. Warm your hands, hang your arm down, and prick the side of the fingertip for better blood flow. If it still doesn't work, get in touch.
How do I return my sample to the lab?
In the included return envelope with free medical shipping. Drop it in the mailbox; the lab processes your sample as soon as it arrives. For some tests it's important to send it the same day — the instructions make this clear.
What if I have questions or something doesn't work?
Feel free to contact us via WhatsApp, email or phone. We're happy to help you before, during or after your test. If the collection doesn't work, we'll arrange a solution or send new materials — no hassle.
Didn't find what you're looking for? Request a custom test
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Received a packet with everything needed, went to a walk in clinic (Amsterdam DC Clinic) where my blood was drawn and I was out the door within 5 minutes, and then after posting the samples, received results 2 days later. Results were easy to understand as well. Amazing service, would highly recommend!