Reasoning GP · Algorithm · 1-page summary
Proteinuria in adults
For: adults with dipstick or incidental proteinuria in primary care. Not for: children (separate paediatric pathway) or proteinuria in pregnancy (obstetric pathways, NICE NG133); suspected pre-eclampsia is in block 2.
Core rule: proteinuria is a marker, not a diagnosis — quantify with an ACR, never the dipstick alone, confirm it persists and stage by eGFR and ACR. A normal ACR does not exclude myeloma.
0Stop — call 999 now
- Sudden severe breathlessness, chest pain, a seizure or collapse → 999
- Pregnant after 20 weeks with a seizure or collapse (suspected eclampsia) → 999
- On an ACEi/ARB with K⁺ ≥6.5 mmol/L, ECG changes or symptoms (palpitations, syncope, chest pain, muscle weakness) → 999. K⁺ 6.0–6.4 → stop the ACEi/ARB and other contributors, urgent ECG; unwell or AKI → Same-day hospital; well → repeat within 1 day after renal/medical discussion.
1Triage — quantify first (NICE NG203)
| Result | Action |
|---|---|
| Dipstick + | Early-morning ACR; exclude UTI, menstruation, exercise, fever |
| ACR 3–70 | Repeat early-morning ACR to confirm |
| ACR ≥70 | No repeat needed; nephrology (unless due to diabetes and already treated) |
| Dipstick +, ACR low | PCR + myeloma screen — do not reassure |
Stage A1 <3 · A2 3–30 · A3 >30 mg/mmol, plus G1–G5. CKD = ACR >3 or eGFR <60 for >3 months.
2Screen — renal and haematological emergencies
- Rapidly progressive GN / AKI: proteinuria + haematuria + rising creatinine + hypertension ± rash, haemoptysis; oliguria → Same-day
- Nephrotic: oedema, low albumin, frothy urine (PCR >300 or ACR >250 approx.) → Urgent nephrology discussion; Same-day if severe oedema, AKI, thrombosis, infection or unstable.
- Myeloma: aged ≥60 with persistent bone pain or unexplained fracture → offer FBC, calcium, ESR/PV, serum electrophoresis, free light chains; suggestive → Suspected cancer. AKI, symptomatic hypercalcaemia, cord compression → Same-day
- Pre-eclampsia: >20 weeks, new proteinuria (PCR ≥30 or ACR ≥8, not a first-morning sample) + BP ≥140/90 → Same-day maternity assessment.
- Malignant hypertension: BP ≥180/120 with retinal haemorrhage or papilloedema, or life-threatening symptoms → Same-day specialist.
- Haematuria (NG12): unexplained visible at ≥45, or non-visible at ≥60 with dysuria or raised WCC → Suspected cancer urology, plus renal work-up.
3Assess
☐ U&E/eGFR, bicarbonate, HbA1c, FBC, lipids, bone profile, albumin ☐ Dipstick for blood ☐ Culture if UTI possible ☐ BP; drugs incl. NSAIDs, lithium, OTC and herbal ☐ Pregnancy? ☐ KFRE at G3–G5
Consider a myeloma screen if protein is disproportionate to ACR, or unexplained anaemia, renal impairment, hypercalcaemia, bone pain, weight loss or raised ESR/PV. GN picture → immunology with urgent renal advice.
4Classify — only if blocks 0–2 are negative
- Transient — fever, UTI, exercise, heart failure → retest when well.
- Orthostatic — younger, absent on early-morning ACR → reassure.
- Diabetic / hypertensive (commonest) — long duration, retinopathy, gradual ACR rise, bland urine → block 5.
- Glomerulonephritis — haematuria, casts, hypertension, rapid change, systemic features → urgent renal advice.
- Overflow (myeloma) — older, anaemia, high calcium or ESR, ACR low for total protein → myeloma screen.
- Uncertain — confirm ACR, eGFR trend; renal advice and guidance.
5Treat — renoprotection; doses: NICE/SPC, BNF, local formulary
- ACEi or ARB: offer if diabetes + ACR ≥3, hypertension + ACR >30, or any ACR ≥70; titrate to maximum tolerated. Not routinely if K⁺ >5.0. U&E 1–2 weeks after each change. Never ACEi + ARB; stop if pregnant.
- SGLT2 inhibitor add-on: eGFR 20 to <45, or 45–90 with ACR ≥22.6 or type 2 diabetes. Not in type 1 diabetes.
- BP 120–129/<80 if ACR ≥70, else 120–139/<90. Offer atorvastatin 20 mg. Stop NSAIDs.
- Lifestyle: less salt, stop smoking, weight; sick-day advice; vaccines per Green Book.
6Refer routinely and review
- Nephrology: ACR ≥70 (unless diabetic and treated), ACR ≥30 + haematuria, eGFR fall ≥25% with category change or ≥15 mL/min in 12 months, KFRE >5%, BP uncontrolled on ≥4 drugs, genetic or rare cause.
- Possible MGUS (small paraprotein) → discuss with haematology, do not reassure.
- Monitor eGFR per NG203 Table 2, ACR individualised; code CKD.
7Never reassure by
- A normal ACR in an older patient — overflow light chains are missed.
- A negative dipstick — it does not detect Bence Jones protein.
- A single dipstick or a single eGFR.
- "Orthostatic" without an early-morning ACR.
- A urology referral — do not delay urgent renal assessment.
- Labelling it chronic before retesting once the patient is well.
8Safety-net — say it, then document it
999 “If you suddenly become very short of breath, get chest pain, have a fit or collapse, call 999.” Same-day “If you notice swelling of your ankles or face, very frothy urine, blood in your urine or you pass much less urine, contact us the same day.”
Recheck U&E after each ACEi/ARB/diuretic change and in dehydrating illness. The myeloma safety-net never fully closes in older patients with unexplained proteinuria.
✓Safe to leave primary care only if — all five, documented
No block 0–2 feature
ACR confirmed (repeat if 3–70); UTI excluded
Staged G and A; myeloma screen considered
ACEi/ARB, SGLT2i, statin assessed; U&E booked
Referral decision, review and safety-net recorded
Summary of the full Reasoning GP proteinuria algorithm, which holds the history, differential, investigations, lifestyle, monitoring and evidence. Sources: NICE NG203 (CKD), NG12 (suspected cancer, updated April 2026), NG133 (hypertension in pregnancy), NG136, NG238, TA1075, TA942, TA877; UKHSA Green Book. Clinical reference — follow local renal, obstetric and cancer pathways and check doses: NICE/SPC, BNF.