Urine ACR (albumin:creatinine ratio)

Diabetes (or CKD with diabetes)

  • ACR < 3
    • no action

 

  • ACR 3-30 + diabetes
    • confirm it is early morning sample
    • dipstick to check for microscopic haematuria
    • ask patient to repeat two further early morning ACRs within one month
    • if at least two out of three are positive
      • consider ACE-I (irrespective of BP)
      • modify CV risk factors – smoking, diet, lifestyle, statins
      • improve glycaemic control

 

  • When to refer
    • CKD3b with proteinuria
    • Deteriorating renal function
      • Cr > 150mmol/L
      • Cr risen 30% in last twelve months
      • Progressively falling eGFR (>10ml/min/1.73m2) within last twelve months
    • Microalbuminuria with persistent haematuria
    • Persistent hypertension
    • Persistently abnormal potassium, calcium, phosphate

 

CKD

  • ACR < 30
    • no action

 

  • ACR 30-70 without haematuria
    • confirm it is early morning sample, dipstick to check for microscopic haematuria, ask patient to repeat two further early morning ACRs within one month
      • if confirmed, actively manage in primary care to reduce progression of CKD (NICE CG73)

 

  • ACR 30-70 with haematuria
    • renal referral (urgency depends on suspected cause)

 

  • ACR 70 – 250
    • routine renal referral

 

  • ACR > 250
    • indicates nephrotic syndrome (along with low serum albumin)
      • Urgent renal referral
Notes

  • An early morning sample is used as there is increased risk of false positive results with random samples

 

  • Causes of increased albumin loss not due to intrinsic renal disease
    • Menstrual contamination
    • Vaginal discharge
    • Uncontrolled hypertension
    • Symptomatic UTI
    • Uncontrolled diabetes
    • Heart failure
    • Intercurrent illness
    • Strenuous exercise

 

  • both micro- and macroalbuminuria are stronger predictors of cardiovascular mortality than of end-stage renal failure, only a minority of patients with microalbuminuria will progress to end-stage renal failure, because death from a cardiovascular cause commonly occurs before renal failure has developed

 

  • blood pressure target
    • if raised ACR, aim for BP < 130/80