Synopsis
Detect and quantify urinary protein accurately, distinguish albumin, tubular and overflow mechanisms, recognise nephrotic or nephritic urgency and use albuminuria to guide CKD risk and treatment.
- Use urine albumin-to-creatinine ratio as the first-line quantitative test in non-pregnant adults because it detects lower-level albumin leakage better than dipstick or PCR.
- NICE classifies A1 as ACR below 3 mg/mmol, A2 as 3 to 30 mg/mmol and A3 as above 30 mg/mmol; albuminuria changes risk even when eGFR is preserved.
- Confirm an ACR from 3 to 70 mg/mmol on a subsequent early-morning sample in a stable adult. NICE does not require confirmation before action when the initial ACR is at least 70 mg/mmol.
Key red flags
Generalised oedema, very heavy proteinuria, low serum albumin and often high lipids suggests nephrotic syndrome. Unilateral leg swelling, pleuritic pain, fever or abdominal pain may indicate thrombosis or infection.
Investigation priorities
Confirm and classify albumin leakage while reducing postural and concentration variation.
Management branches
Positive dipstick protein or ACR at least 3 mg/mmol without current severe illness.
- Check UTI, menstruation, exercise, fever, glucose and heart failure, then confirm ACR 3 to 70 using an early-morning sample; do not delay action for ACR at least 70.
- Assign A category with eGFR G category, check blood pressure and diabetes, review medicines and calculate progression or KFRE where NICE applies.
Key medicines
ACE inhibitor or angiotensin receptor blockerTitrate to the highest licensed dose tolerated when NICE indications are met, using blood pressure, potassium, creatinine and volume-status monitoring.
SGLT2 inhibitorSelect the licensed agent and dose using current NICE indication, eGFR range, diabetes status and SmPC, alongside standard kidney-protective care.