Urine · 3 analyses
Microalbumin (albumin/creatinine ratio)
Measures albumin and creatinine in urine and calculates their ratio. For people with diabetes, high blood pressure or kidney disease in the family.
€ 23,00
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Other analyses · Urine
Albumin/creatinine ratio
Calculated ratio of albumin to creatinine in urine; the measure the NHG uses for protein loss in kidney damage.
At a glance
- Measured in urine
- In 1 test panel
- No special preparation
Explanation
Albumin/creatinine ratio: what is measured?
The albumin/creatinine ratio (ACR) is not a separate measurement but a calculation. The laboratory measures albumin and creatinine in the same urine sample and divides albumin by creatinine. Because creatinine is excreted at a fairly constant rate, this division makes the result largely independent of how much you have drunk. This way, a single urine sample can be used instead of a 24-hour collection. The result is given in milligrams of albumin per millimole of creatinine (mg/mmol) or per gram of creatinine (mg/g).
What can it detect?
- Raised albumin in the urine (albuminuria) and its severity according to the Dutch GP guideline (NHG) on chronic kidney damage
- Early kidney damage in diabetes or high blood pressure, even with a normal eGFR
- Increased risk of cardiovascular disease: albumin in the urine counts toward cardiovascular risk
Result
What does the result mean?
Albumin/creatinine ratio too high
The NHG guideline divides the ratio into three groups: below 3 mg/mmol is normal, 3 to 30 mg/mmol moderately raised and above 30 mg/mmol severely raised (in mg/g roughly below 30, 30 to 300 and above 300). Chronic kidney damage is present if the ratio stays raised on repeated testing over a period of at least 3 months. A raised ratio usually points to damage to the kidney filters due to diabetes or high blood pressure, sometimes to a kidney disease, and goes with a higher risk of further decline and of cardiovascular disease. A single raised value can also be temporary: after heavy exercise, with fever, a urinary tract infection, during menstruation or with high blood sugar. In people with little muscle mass the ratio is somewhat higher, because they excrete less creatinine.
Albumin/creatinine ratio too low
A low ratio is favorable and fits kidneys that let almost no albumin through; a value that is too low does not exist as a problem. In people with a lot of muscle mass, such as strength athletes, the ratio is somewhat lower because they excrete more creatinine. A normal ratio does not rule out reduced filtering function of the kidneys; that requires the eGFR in blood.
After an abnormal result
With a raised ratio, the GP rules out a urinary tract infection, repeats the measurement in morning urine and has the eGFR in blood measured. If the ratio is still raised after 3 months, the GP diagnoses chronic kidney damage, determines the risk stage and pays extra attention to blood pressure, glucose and cholesterol. With a severely raised ratio, a rapidly declining kidney function or albumin together with blood in the urine, referral to an internist-nephrologist may follow.
Reliability
How reliable is the test?
According to the Dutch GP guideline (NHG) on chronic kidney damage, the albumin/creatinine ratio together with the eGFR is the basis for diagnosing kidney damage and classifying the risk. The ratio thus adds something beyond the albumin concentration alone, which depends on how concentrated the urine is. The Dutch medical specialists' guideline (FMS) uses the same classification into normal, moderately raised and severely raised. Because albumin in the urine varies from day to day, a raised ratio is always confirmed with a repeat measurement.
What can affect the result?
- Heavy exercise, fever, a urinary tract infection, menstruation and high blood sugar can raise the ratio temporarily.
- Muscle mass affects the excretion of creatinine: with little muscle mass the ratio is higher, with a lot of muscle mass lower.
- Morning urine gives the most comparable result; a sample later in the day can give a different result.
- Chronic kidney damage can only be diagnosed if the abnormality has been present for at least 3 months; a single result is not a diagnosis.
Who it is for
Who is the test useful for?
Useful for
Useful for people with diabetes, high blood pressure, cardiovascular disease, kidney disease in the family or a reduced eGFR; in diabetes and known kidney damage, the ratio is usually checked every year. The ratio means most together with the eGFR in blood. In healthy adults without risk factors, the chance of a raised ratio is small and a slightly raised value is often temporary.
How common is it?
Chronic kidney damage affects about 1 in 10 adults in the Netherlands, more often at older ages and in people with diabetes and high blood pressure. Raised albumin in the urine is often the first sign. In about 5 in 100 Dutch people, chronic kidney damage is known to the GP; so many people with kidney damage do not know it.
NHG guideline on chronic kidney damage; NIVEL primary care registrations (2021)
Drawbacks and risks
- A temporarily raised value after exercise or with an infection can, without a repeat measurement, wrongly look like kidney damage and cause unnecessary worry.
Get tested
Albumin/creatinine ratio: test panels
Albumin/creatinine ratio is part of these test panels. You order online and have your blood drawn at a collection point or collect the sample at home.
Evidence
Sources
This explanation is based on Dutch guidelines and independent information. It is general information, not a diagnosis. Discuss an abnormal result with your GP.
More about risks and results- NHG-Standaard Chronische nierschade (M109)
- FMS Richtlijn Chronische nierschade: Bepaling van nierfunctie en albuminurie
- NVKC, allesovertesten.nl: Microalbumine
- Thuisarts.nl: Ik heb nierschade
- NIVEL (2021): Chronische nierschade in de huisartsenpraktijk, prevalentie en behandeling conform de NHG-standaarden