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Understanding ACR and urine protein
Protein in urine can be an early sign that the kidney filters are under stress or damaged. ACR focuses on albumin, the main blood protein that commonly leaks through affected kidney filters, and adjusts for how concentrated the urine sample is.
This guide helps you understand terms and prepare questions. It cannot diagnose a condition or tell you to change treatment. Seek local medical care for urgent or severe symptoms.
Start here
Three points to keep
- ACR means urine albumin-to-creatinine ratio.
- Persistent albuminuria matters even when eGFR is preserved.
- A higher result is often confirmed because temporary factors can affect it.
ACR, PCR, and dipsticks
ACR measures albumin relative to creatinine in a spot urine sample. PCR measures total protein relative to creatinine. A dipstick is a quick screening test but is affected by urine concentration and is not as precise for lower levels of albumin.
The tests are related but not interchangeable. Record the test name, value, and unit rather than comparing the numbers directly.
How ACR is categorized
KDIGO groups albuminuria into three categories. These categories help estimate risk when combined with eGFR and the cause of kidney disease.
| Category | mg/g | mg/mmol | General description |
|---|---|---|---|
| A1 | Below 30 | Below 3 | Normal to mildly increased |
| A2 | 30–300 | 3–30 | Moderately increased |
| A3 | Above 300 | Above 30 | Severely increased |
Why a result may be repeated
Albumin excretion varies. An early-morning sample is often preferred for confirmation because it may reduce some day-to-day variation.
- Recent vigorous exercise
- Fever, infection, or a urinary tract infection
- Menstruation or visible blood contaminating the sample
- Markedly high blood pressure or blood glucose
- Temporary illness, dehydration, or heart failure
What persistent albuminuria can change
Persistent albuminuria can support a CKD diagnosis, raise estimated kidney and cardiovascular risk, and influence treatment or follow-up. A clinician may also investigate the pattern of blood, protein, and other urine findings to identify a cause.
Very foamy urine is not a reliable measurement by itself. New visible blood, major swelling, reduced urination, or rapidly worsening symptoms should be assessed promptly.
For your next visit
Questions worth taking with you
- 01Was this test ACR, PCR, or a dipstick, and which unit did the laboratory use?
- 02Should the result be confirmed with an early-morning sample?
- 03How does my urine result change my combined kidney-risk category?
Evidence trail
Sources
ENKI prioritizes current clinical guidelines and public-health sources. Links open on the publisher's website.
Published by the ENKI Health Editorial Team under our editorial policy.