Urine creatinine test: what the result means
500–2,000 mg/day; on the MedlinePlus page the same limits are also written as “4,420 to 17,680 mmol/day” (the comma there is a decimal separator, i.e. 4,420 = 4.42 and 17,680 = 17.68, and not thousands). Recalculated using the molar mass of creatinine, 113.12 g/mol: 500 mg ≈ 4.42 mmol, 2,000 mg ≈ 17.68 mmol.
- Updated
- 2026-09-10
- Every number with its source
What urine creatinine shows
Creatinine is a waste product of metabolism formed in the muscles as creatine breaks down; the amount in the blood depends on muscle mass and is fairly constant. The kidneys remove creatinine from the blood completely, so the amount in urine directly reflects how kidney filtration is working. For the test, all the urine passed over 24 hours is usually collected, because the result of a single sample can fluctuate depending on fluid intake and the time of day. Urine creatinine is often assessed not on its own but together with other markers — for example, when calculating creatinine clearance (how much blood the kidneys clean per minute) or the albumin-to-creatinine ratio, which helps to assess protein loss through the kidneys. That is why a single urine creatinine result is usually only part of a broader assessment of kidney function, and not a diagnosis on its own.
Reference range
| Group | Range, mmol/day | Source |
|---|---|---|
| Adults (24-hour urine) 500–2,000 mg/day; on the MedlinePlus page the same limits are also written as “4,420 to 17,680 mmol/day” (the comma there is a decimal separator, i.e. 4,420 = 4.42 and 17,680 = 17.68, and not thousands). Recalculated using the molar mass of creatinine, 113.12 g/mol: 500 mg ≈ 4.42 mmol, 2,000 mg ≈ 17.68 mmol. | 4.4–17.7 | MedlinePlus Reviewed 2025-07-01 |
When the test is done
- To assess kidney function and filtration capacity — together with creatinine in the blood and creatinine clearance
- When there is raised blood pressure, tiredness, or noticeable changes in urination
- In diabetes mellitus or a systemic autoimmune disease that can damage the kidneys
- When monitoring a known kidney disease over time
- To assess whether the result of another urine test (for example protein or albumin) matches the real concentration level, correcting for creatinine
How to prepare
- Most often all the urine passed over 24 hours is collected: the first morning void is not collected, but every later one during the day is — and the sample is kept cold
- Your doctor may ask you not to eat meat for the 24 hours before the test, because meat can temporarily raise the result
- It is worth mentioning in advance, before the test, if your period has started or you have haemorrhoidal bleeding
A raised result
A raised urine creatinine is most often linked not to a disease but to how much meat was eaten or how much fluid was drunk before the test. According to MedlinePlus, eating a lot of meat and muscle breakdown (for example after intense physical exercise or an injury) can temporarily raise the amount in urine. According to Medicina practica, dehydration has a similar effect.
- Eating a lot of meat (protein) before the test
- Breakdown of muscle tissue (for example after heavy physical exertion or an injury)
- Dehydration (a lack of fluid in the body)
After a raised result — what to discuss with a doctor
- Whether the recommendations on meat and fluids were followed on the day of the test
- Creatinine in the blood and creatinine clearance — for the overall picture of kidney function
- When to repeat the test, following the preparation recommendations
A reduced result
A reduced urine creatinine can indicate that the kidneys are filtering the blood less well. According to MedlinePlus, the causes include damage to the kidney tubules, kidney failure, reduced blood flow through the kidneys, a kidney infection or a blockage of the urinary tract. Medicina practica adds that a low result can also be caused by reduced muscle mass.
- Damage to the kidney tubules
- Kidney failure
- Reduced blood flow through the kidneys
- A kidney infection or a blockage of the urinary tract
- Reduced muscle mass
After a reduced result — what to discuss with a doctor
- Creatinine in the blood, creatinine clearance and GFR — so that it is clear how kidney filtration is working
- Whether there is an obstruction to urine flow (for example stones or another cause)
- An assessment by a family doctor if the result recurs
Full site in Lithuanian: proactiva.app
Frequently asked questions
›What is the normal range for creatinine in urine?
According to MedlinePlus, in urine collected over 24 hours the normal amount is 500–2,000 mg a day, which corresponds to approximately 4.4–17.7 mmol a day. The exact laboratory range can differ depending on how the sample was collected — you will find it on your own result sheet.
›Why is creatinine tested in urine and not only in the blood?
The kidneys remove creatinine from the blood completely, so the amount in urine shows how effectively the kidneys are filtering the blood. Most often urine creatinine is assessed together with creatinine in the blood, to calculate creatinine clearance.
›How should the urine sample be prepared for this test?
Most often all the urine passed over 24 hours has to be collected, skipping the first morning void. Your doctor may ask you not to eat meat for 24 hours before the test, because that can temporarily raise the result.
›Does a raised urine creatinine mean kidney disease?
Not always. According to MedlinePlus, the most common cause of a raised result is eating a lot of meat or muscle breakdown after physical exercise, rather than kidney disease. It is always worth discussing the result with a doctor, together with other kidney markers.
›What does a reduced urine creatinine mean?
A reduced amount can indicate poorer kidney filtration — for example because of damage to the kidney tubules, reduced blood flow or a blockage of the urinary tract. This has to be assessed together with creatinine in the blood and creatinine clearance.
›How much does a urine creatinine test cost in Lithuania?
The price depends on the laboratory and on how the sample is collected (a single sample or a 24-hour urine collection). It is worth checking the exact price in your city in the price list of your chosen laboratory before booking the test.
Sources
Related markers
This site is not an emergency service. If severe chest or head pain, breathlessness, confusion, difficulty speaking, heavy bleeding or another acute problem has come on suddenly — do not wait for tests, call 112.
This information is not a diagnosis and does not replace a consultation with a doctor. Reference ranges depend on the laboratory, your age and sex — always compare your result with the range printed on your own report.