Works out the urine albumin-to-creatinine ratio (ACR) from a urine albumin and urine creatinine result, and places it in the KDIGO A-categories used to assess kidney damage.
| KDIGO category | ACR (mg/g) | Meaning |
|---|---|---|
| A1 | Below 30 | Normal to mildly increased |
| A2 | 30–300 | Moderately increased |
| A3 | Above 300 | Severely increased |
A single raised ACR does not diagnose kidney damage — exercise, fever, urinary infection and concentrated urine can all raise it for a short time, so abnormal results are normally confirmed with repeat samples. Read together with eGFR, ACR gives the fuller picture of kidney health.
What does urine ACR measure?
ACR (albumin-to-creatinine ratio) measures how much albumin protein is leaking into the urine, corrected for how concentrated the urine is. Albumin in urine is one of the earliest signs of kidney damage, often appearing before eGFR falls.
What are the ACR categories?
KDIGO categories are A1 (below 30 mg/g, normal to mildly increased), A2 (30–300 mg/g, moderately increased — historically called microalbuminuria), and A3 (above 300 mg/g, severely increased — macroalbuminuria).
If my ACR is high once, do I have kidney disease?
Not necessarily. Exercise, fever, infection, and very concentrated urine can raise ACR temporarily, so guidelines recommend confirming an abnormal result with repeat testing — typically two of three samples over several months — before calling it persistent.