Urine ACR explained

ACR measures a little protein called albumin in your urine. It is one of the earliest signs the kidneys are under strain, and it often improves.

Your details

ACR of 4.5 mg/mmol

4.5 mg/mmol

A2: moderately increased

A1under 3 mg/mmol
A23 to 30 mg/mmol
A3over 30 mg/mmol
In mg/g (US style)40
Repeat sampleadd it when you have it to see whether the result is confirmed

Between 3 and 70, NICE asks for a repeat on an early morning sample to confirm it, since a single sample can read high for short term reasons.

Your GP or practice nurse will look at this alongside your eGFR and blood pressure. Ask them what it means for you.

The working

An ACR of 4.5 mg/mmol

4.5 is between 3 and 30, so it is A2, moderately increased. In US style units that is 4.5 x 8.84 = 40 mg/g. NICE asks for a repeat on an early morning sample for any first result between 3 and 70, so this result is a reason to repeat rather than worry.

The categories

A1 to A3

Category	mg/mmol (UK)	mg/g (US, rounded)
A1, normal to mildly increased	under 3	under 30
A2, moderately increased	3 to 30	30 to 300
A3, severely increased	over 30	over 300

At 70 mg/mmol or more, NICE suggests a kidney specialist assessment, unless diabetes explains it and is already being treated.

Who gets tested

Why your GP asked for it

Diabetes, type 1 or type 2
High blood pressure
Heart disease or a past kidney injury
An eGFR under 60
Family history of kidney failure

Repeat tests, diabetes and blood

What NICE does next

Repeat sample: a first ACR between 3 and 70 is repeated on an early morning sample. If both are 3 or more, NICE treats it as confirmed (NG203 1.1.12 and 1.1.13). A result of 70 or more does not need a repeat.
Diabetes: for adults with kidney disease and diabetes, NICE recommends offering an ACE inhibitor or ARB when the ACR is 3 or more (NG203 1.6.7). Without diabetes the threshold is higher.
Blood in the urine: an ACR over 30 together with blood on a dipstick is one of the NICE reasons to refer to a kidney specialist (NG203 1.5.5).

Read with care

What this cannot tell you

Confirm a resultOne sample needs repeating to be sure.
Measure kidney filteringThat is what eGFR is for; the two go together.
Use dipstick resultsOnly a lab ACR fits these categories.

Questions

Common questions

What is a normal urine ACR?

Under 3 mg/mmol is the normal to mildly increased group, A1.

Why do I need a morning sample?

NICE asks for an early morning sample to confirm a result between 3 and 70, as it gives the most reliable reading.

Can ACR go down?

Often, yes, with good blood pressure and sugar control and some medicines your GP may suggest.

Sources

Last checked 21 October 2026. Spotted something wrong? Tell us and we will fix it.

Talk your results through

If a result worries you, book a chat with your GP or practice nurse, or ask a pharmacist. Call NHS 111 if you feel unwell and are not sure what to do, and 999 in an emergency.