Proteinuria and Haematuria – an update

Alex Heaton

11.02.2009

What is normal?

• Normal 80 +/- 25 mg/day (<150 mg is quoted as upper normal limit).

• Adolescents up to 300 mg/day (♀ 10-16 years, ♂ 12-18 years)

Measurements of proteinuria

• Dipstick tests

• 24 hour urinary protein

• Urine protein/creatinine ratio

• Urine albumin/creatinine ratio

Why bother testing urine?

• Detection of renal disease

• Cardiovascular risk factor

Clinical significance of proteinuria

Proteinuria on dipstick in healthy patient

? Any systemic disease, e.g hypertension,

diabetes mellitus likely renal disease

>1 gram a day likely renal disease

>3.5 g/day likely glomerular disease

Protein in urine – what next?

• establish persistent proteinuria

• clinical assessment

• interpreting test results

Step 1. Establish persistent proteinuria

proteinuria (1+ or more)↓

exclude urinary infection↓

repeat urinalysis after at least one week ↓ ↓1+ or more continue trace or negative –

no action

Step 2. Initial assessment if persistent proteinuria 1+ or more

• send early morning urine for albumin/creatinine ratio

• blood tests: U & E’s, fasting glucose, cholesterol and albumin

• Check blood pressure

Step 3: What to do with an albumin/creatinine(mg/mmol) result

• <5 within reference range• 5-30 does not indicate renal disease

but consider cardiovascular risk factors

• 31-70 check 6 monthly blood pressure and ACR. No need to refer to nephrology unless patient also has haematuria, severe hypertension, eGFR <60 or a systemic disease

• >70 refer to Nephrology

Proteinuria - summary

• urine protein testing is worthwhile (vs blood)

• use dipstix to decide when to test further

• albumin : creatinine ratio instead of 24 hour collection.

• use ACR to decide who to refer

Haematuria

• frank haematuria – high yield on investigation

• microscopic haematuria

+ symptoms – high yield

- symptoms – low or very low yield

Microscopic haematuria

• trace blood + no symptoms – no investigation

• 1+ or more, confirmed on repeat testing – investigate/refer?

Urology Referral

• male

• >40 years

• smoker

• industrial exposure to hydrocarbons

• chemotherapy

= cystoscopy

Renal referral

• eGFR < 60

• proteinuria (ACR >30)

• hypertension

• family history

= nephrology

What tests?

• eGFR

• plain urinary tract X-ray

• ultrasound

• ? urine microscopy ? cytology

Summary - haematuria

• try to avoid testing asymptomatic patients

• most asymptomatic patients do not need referral?

• limited benefit from renal referral unless specific indication.