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What is uACR, and what is a normal result?

A uACR is one line on a kidney lab report, and a single number is easy to over- or under-read. Repeat tests and results from different doctors change how it reads.

Arun Verma, co-founder of Triangle · 2026-10-17

This is not clinical evidence and not medical advice. It does not replace your care team. Discuss anything here with your clinician before you act on it.

What is uACR?

uACR is a urine test that compares the amount of albumin, a protein, with the amount of creatinine, a waste product, in a urine sample. The letters stand for urine albumin-to-creatinine ratio. A healthy kidney doesn't let albumin pass from the blood into the urine, NIDDK says, and a damaged kidney lets some through. Too much albumin in the urine is called albuminuria. Your lab report may not say uACR. MedlinePlus lists other names, including albumin-creatinine ratio, ACR and microalbumin, urine. The National Kidney Foundation (NKF) says to focus on the result with "ratio" in its name, such as "alb/creat ratio" or "albumin/creat ratio, random urine".

What is a normal uACR result?

Below 30 mg/g. NIDDK calls a urine albumin result of 30 mg/g or less normal and anything above 30 mg/g a possible sign of kidney disease, and KDIGO's lowest albuminuria category, A1, is below 30 mg/g. Lower is better: NIDDK says the less albumin in your urine, the better. Exactly 30 is where the wording splits. NIDDK counts it as normal, A1 stops below it, and KDIGO's criteria for chronic kidney disease list an ACR of 30 mg/g or higher as a marker of kidney damage when it lasts at least 3 months. If a result sits right on the line, a fair question for your nephrologist is which side your lab and your team use.

What do the A1, A2 and A3 categories mean?

They are KDIGO's three albuminuria bands: A1 is below 30 mg/g (normal to mildly increased), A2 is 30 to 300 (moderately increased) and A3 is above 300 (severely increased). KDIGO's table gives the same bands in mg/mmol, as below 3, 3 to 30 and above 30, so it helps to know which unit your report uses. The edges are printed two ways. KDIGO's monitoring grid and NKF say 30 to 299 and 300 or higher. NIDDK's clinician page notes the middle band has traditionally been called microalbuminuria and the top one macroalbuminuria, says the 300 cutoff only roughly matches the lower limit of the dipstick, that the cutoffs come from laboratory methods rather than clinically relevant endpoints, and that urine albumin is a continuous risk factor.

How is the sample taken, and why a ratio?

Usually one urine sample, given at a clinic or lab. KDIGO prefers a first-morning midstream sample. NIDDK's clinician page says a random sample collected in the office is acceptable if a first-morning one isn't available, and that a 24-hour collection isn't necessary for routine assessment. MedlinePlus says a 24-hour sample is usually the follow-up to an abnormal single sample. The ratio is there because urine can be dilute or concentrated. NIDDK's clinician page says that, unlike a dipstick, UACR corrects for variation in urine concentration, and that providers use it to estimate how much albumin would pass into the urine over 24 hours.

Can one uACR result be a blip?

Yes. A single result can be temporary, which is why an abnormal one is usually checked again. KDIGO defines CKD as abnormalities present for at least 3 months and says not to assume chronicity from a single abnormal ACR or eGFR, and MedlinePlus says people usually have two more tests over the next three to six months. Exercise, certain medicines, fever and inflammation can push a single result up, and so can blood in the urine, menstruation and a symptomatic urinary infection. For someone already living with CKD, KDIGO's first step with a change in eGFR or ACR is to repeat the test. You could ask whether anything around the sample, such as a workout or a fever, might have affected it, and whether any medicines or supplements could.

How does uACR fit with eGFR on the CKD staging grid?

Side by side: eGFR sets the G part of the stage and uACR sets the A part. KDIGO classifies CKD by cause, GFR category (G1 to G5) and albuminuria category (A1 to A3), and says the system rests on those two dimensions, so a stage can read like G3a, A1. KDIGO's grid is shaded green, yellow, orange and red for rising risk. KDIGO says risk rises with higher stages of both eGFR and albuminuria, which is why it wants both numbers, and that the grid describes populations and is not an individual risk tool. NKF adds that albumin in the urine can be a sign of kidney disease even when eGFR is above 60.

How often is uACR tested?

KDIGO's practice point is at least once a year in people with CKD, and more often for individuals at higher risk of CKD progression when measurement will impact therapeutic decisions. NKF says follow-up ranges from once a year to four or more times a year, depending on your initial uACR, your eGFR and whether you have been diagnosed. A fair question for your team is when your last uACR was and when the next one is due. NKF's own question list starts with "When was the last time I had a uACR test completed?"

How do I read a trend, or compare results from different doctors?

A trend needs more than one result, and results in different units don't line up directly. KDIGO says no clear threshold defines a clinically relevant change in albuminuria, and that overinterpreting small changes can lead to unnecessary changes in care. It also says that for albuminuria monitoring in people with CKD, a doubling of the ACR on a later test exceeds laboratory variability and warrants evaluation. NIDDK's clinician page says stable or lower levels may indicate therapy is effective and increasing or elevated levels may indicate progression. With results from more than one practice, a fair question for whoever ordered each one is which unit and which kind of sample it used. KDIGO prints the categories in both mg/g and mg/mmol, and says a result of 30 mg/g or higher on a random sample should be confirmed with a later first-morning one.

What could I ask my nephrologist about my uACR?

You could ask whether your latest uACR has been confirmed by a repeat, which category your lab and your team put it in, how it sits with your eGFR on the staging grid, and when the next one is due. NKF's list for your healthcare team includes "Should I have my uACR test repeated to confirm my results?" and "What do my uACR results mean in the context of my overall health?" No source says what a given number means for a given person; that is a question for the people who know your history.

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