Suspected Glomerular Disease (Adults)
Proteinuria, glomerular haematuria, or falling kidney function in an adult. Not for children.
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NephrologyDiagnostic
Glomerulonephritis Evaluation (KDIGO 2021)
Glomerulonephritis Evaluation (KDIGO 2021): Suspected Glomerular Disease (Adults) → Emergency First: RPGN or Lung Haemorrhage? → Initial Tests (All Pati...
Pathway Overview
17 steps
Algorithm Steps
17 total
01Start 02Warning Emergency First: RPGN or Lung Haemorrhage?
eGFR falling over days to weeks with blood and protein in the urine, or haemoptysis or hypoxia: same-day nephrology. Treatment can start before biopsy. Check potassium, fluid status and acid-base: life-threatening hyperkalaemia, pulmonary oedema or acidosis needs urgent dialysis assessment.
- Send urgently: ANCA (MPO, PR3), anti-GBM antibody, C3, C4, ANA, anti-dsDNA
- Suspected anti-GBM disease: start glucocorticoids, cyclophosphamide and plasma exchange without waiting for biopsy
- MPO- or PR3-ANCA positive with a vasculitis picture: do not delay immunosuppression for biopsy; consider plasma exchange if creatinine >300 µmol/L, dialysis, or lung haemorrhage with hypoxaemia
03Action Initial Tests (All Patients)
Confirm and measure the abnormality.
- Urine microscopy: dysmorphic red cells, acanthocytes, red cell casts; urine culture
- Urine protein/creatinine ratio (UPCR); 24-h urine protein when a treatment decision depends on the value
- Creatinine and eGFR; repeat to see the rate of change
- Serum albumin (result depends on the lab method), electrolytes, FBC, HbA1c
- Blood pressure, oedema; rash, joint, lung, sinus symptoms; new medicines (for example NSAIDs)
04Action Classify the Clinical Syndrome
The syndrome decides the extra tests in the next steps.
- Nephrotic: proteinuria ≥3.5 g/day (UPCR ≥300 mg/mmol), low serum albumin, oedema
- Nephritic: glomerular haematuria (red cell casts), hypertension, oedema, often AKI; proteinuria usually below nephrotic range
- Mixed: features of both; do both sets of extra tests
- Isolated: haematuria or proteinuria only, with normal eGFR and BP
05Action Nephrotic or Mixed: Extra Tests
Look for the cause, including secondary causes.
- Anti-PLA2R antibody (membranous nephropathy)
- Hepatitis B, hepatitis C, HIV and syphilis serology
- ANA, C3, C4
- Serum and urine protein electrophoresis with immunofixation; serum free light chains
- Fasting lipids
- Membranous nephropathy: age-appropriate cancer screening
06Action Nephritic or Mixed: Extra Tests
Look for vasculitis, anti-GBM disease, lupus, infection and complement disease.
- C3, C4
- ANCA (MPO, PR3) and anti-GBM antibody
- ANA, anti-dsDNA
- ASOT or anti-DNase B if recent throat or skin infection
- Blood cultures if fever or a new murmur (endocarditis)
- Cryoglobulins; hepatitis B and C serology
07Action Isolated Haematuria or Proteinuria: Exclude Other Causes
Normal eGFR and BP. Glomerular disease is possible but often does not need biopsy.
- Haematuria: exclude infection. Visible haematuria, age >40 years, smoking or other risk factors: refer to urology (cystoscopy)
- Proteinuria: repeat to confirm; young person: test a first-morning sample for orthostatic proteinuria
- Persistent haematuria without albuminuria: review each year (urine, ACR, eGFR, BP)
- Albuminuria, falling eGFR or hypertension: refer to nephrology
08Action Kidney Ultrasound
Kidney size, echogenicity, number of kidneys, obstruction.
- Small echogenic kidneys: chronic damage; biopsy has lower yield and higher risk
- Single functioning kidney: relative contraindication to percutaneous biopsy
- Obstruction: treat the obstruction first
09Decision Kidney Biopsy Indicated and Safe?
Adults only. Biopsy when the result will change treatment or give needed prognosis. Children with nephrotic syndrome usually get glucocorticoids without biopsy.
- Usually biopsy: adult nephrotic syndrome; nephritic syndrome; unexplained AKI with active urine sediment
- Treatment may start without biopsy: PLA2R-positive membranous nephropathy (especially normal eGFR), MPO- or PR3-ANCA vasculitis, anti-GBM disease
- Often no biopsy: isolated haematuria with normal eGFR and no proteinuria; typical diabetic kidney disease
- Contraindications: uncorrected bleeding risk, uncontrolled BP, small shrunken kidneys, active kidney infection
- If Yes
10Action Biopsy Indicated: Stop Antithrombotics First
Anticoagulants and antiplatelets raise biopsy bleeding risk. Plan the stop and restart with the prescriber before biopsy.
- DOAC: stop time depends on the drug and kidney function (longer when CrCl is low); a normal INR or APTT does not exclude DOAC effect; follow local protocol and product information
- Warfarin: stop per local protocol and check INR before biopsy. Mechanical valve or recent VTE or stroke: plan interruption with the treating team
- Before biopsy: FBC, coagulation tests, BP control, consent
- Specimen: light microscopy, immunofluorescence, electron microscopy
- After biopsy: monitor BP, pulse, Hb and urine for bleeding per local protocol
11Action Interpret Biopsy Results
Diagnosis, disease activity and chronic damage.
- Nephrotic pattern: minimal change disease, FSGS, membranous, diabetic, amyloid
- Nephritic pattern: IgA nephropathy, lupus nephritis, ANCA GN, anti-GBM, infection-related GN
- MPGN pattern: look for infection (hepatitis C), autoimmune disease, monoclonal gammopathy, C3 glomerulopathy
- FSGS lesion: separate primary FSGS from secondary or genetic FSGS
- Activity guides treatment intensity; chronicity shows damage that will not recover
12Warning Before Immunosuppression: Pregnancy and Infection Checks
Do these before starting. For RPGN or anti-GBM disease, do not delay treatment while results are pending.
- Pregnancy test. Mycophenolate, cyclophosphamide and rituximab are contraindicated in pregnancy: contraception; fertility counselling before cyclophosphamide
- Screen hepatitis B (HBsAg, anti-HBc): rituximab, cyclophosphamide and glucocorticoids can cause fatal reactivation; if positive, start antiviral therapy with hepatology first. Also hepatitis C, HIV, TB; Strongyloides if the patient has lived in an endemic area
- Consider Pneumocystis prophylaxis (trimethoprim-sulfamethoxazole) with high-dose glucocorticoids, rituximab or cyclophosphamide; update vaccines
13Action Disease-Specific Treatment (Specialist)
Confirm the diagnosis first. No immunosuppression for secondary or genetic FSGS, or for low-risk membranous nephropathy. Follow the current KDIGO guideline for the disease.
- Minimal change disease: high-dose oral glucocorticoids
- Primary FSGS: high-dose oral glucocorticoids; cyclosporin or tacrolimus if steroid-resistant
- Membranous: choose by risk of progression: rituximab, cyclophosphamide with glucocorticoids, or CNI-based therapy
- IgA nephropathy (KDIGO 2025): proteinuria ≥0.5 g/day on or off treatment: add targeted-release budesonide or reduced-dose glucocorticoids (with PJP prophylaxis) to supportive care; target <0.5 g/day, ideally <0.3 g/day. Glucocorticoid harm is higher with eGFR <30, diabetes, obesity, latent infection, peptic ulcer or osteoporosis
- Lupus nephritis class III/IV (KDIGO 2024): glucocorticoids with mycophenolate, low-dose IV cyclophosphamide, belimumab combination, or mycophenolate with a CNI (only if eGFR >45 mL/min/1.73 m²); hydroxychloroquine unless contraindicated
- ANCA GN (KDIGO 2024): glucocorticoids with rituximab or cyclophosphamide; avacopan can reduce glucocorticoid exposure
- Anti-GBM disease: glucocorticoids, cyclophosphamide and plasma exchange. Exception: on dialysis at presentation with 100% crescents or >50% global sclerosis and no lung haemorrhage (specialist decision)
14Action Supportive Care for All Patients
Pregnancy: do not use ACE inhibitor, ARB or SGLT2 inhibitor. Type 1 diabetes: no SGLT2 inhibitor (ketoacidosis). Abrupt-onset nephrotic syndrome (possible minimal change disease): do not start ACE inhibitor or ARB (AKI risk).
- ACE inhibitor or ARB at maximum tolerated dose for proteinuria or hypertension; check potassium and creatinine; avoid while kidney function changes fast
- SGLT2 inhibitor if eGFR ≥20 mL/min/1.73 m² with ACR ≥20 mg/mmol, type 2 diabetes or heart failure. Not in type 1 diabetes (ketoacidosis risk)
- BP target: systolic <120 mmHg if tolerated (standardised office BP)
- Oedema: dietary sodium <2 g/day; loop diuretic
- Statin for persistent hyperlipidaemia, by cardiovascular risk
- Nephrotic syndrome: consider prophylactic anticoagulation if albumin <20-25 g/L with other risk factors (highest risk in membranous) after a bleeding-risk review
- Sick days: hold ACE inhibitor or ARB, diuretics and SGLT2 inhibitor when at risk of dehydration
- Response
15Outcome Remission or Stable
Monitor proteinuria, eGFR and BP. Watch for relapse. Continue supportive care, and maintenance immunosuppression where the disease guideline requires it (for example ANCA GN, lupus nephritis).
- No response
16Outcome No Response or Progressing
Specialist review: check adherence and diagnosis, repeat biopsy if it would change treatment, alternative agents or trials, plan for kidney failure care.
If No- No or not yet
17Action No Biopsy Now: Treat or Monitor
Biopsy not needed, not safe, or still pending.
- Diagnosis secure on serology (PLA2R-positive membranous, ANCA vasculitis, anti-GBM): specialist starts disease-specific treatment after the Before Immunosuppression checks
- Biopsy not safe: correct the risk and reconsider, or treat on clinical grounds with a nephrologist
- Isolated haematuria or typical diabetic kidney disease: supportive care and monitoring
- Reconsider biopsy if proteinuria rises, eGFR falls, or new haematuria or systemic features appear
- Serology diagnosis
- Path rejoins step 12Shared downstream outcome
- Supportive care
- Path rejoins step 14Shared downstream outcome
Guideline Source
KDIGO 2021 Clinical Practice Guideline for the Management of Glomerular Diseases (with KDIGO 2024 Lupus Nephritis, KDIGO 2024 ANCA Vasculitis and KDIGO 2025 IgAN/IgAV chapter updates)
Clinical Safety Information
Clinical Decision Support — Not a Substitute for Clinical Judgment
Individual patient factors may require deviation from these recommendations.
Known Limitations
- Adults only. Children with nephrotic syndrome: use the KDIGO 2025 paediatric guideline (glucocorticoids usually without biopsy).
- Disease-specific treatment lines are summaries; doses and regimens must come from the current KDIGO chapter and a nephrologist.
- Antithrombotic stop times before biopsy follow local protocol and product information.
- Does not cover all glomerular diseases (for example C3 glomerulopathy, monoclonal gammopathy, infection-related GN) in detail.
Contraindicated Populations
Children and adolescents under 18 years (use KDIGO 2025 Nephrotic Syndrome in Children guideline)Kidney transplant recipients (recurrent or de novo GN needs transplant-specific pathway)
Applicable Regions
globalAUEUUS
AU: Targeted-release budesonide (Nefecon) and sparsentan were not found on the ARTG (Sep 2026): use the reduced-dose glucocorticoid option or the Special Access Scheme. Strongyloides is endemic in parts of northern and remote Australia.
global: KDIGO 2021 glomerular diseases guideline, updated chapter by chapter (lupus nephritis 2024, ANCA vasculitis 2024, IgAN/IgAV 2025).
Version 2Next review: 2027-09-30
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eGFR (CKD-EPI 2021)
Estimated glomerular filtration rate using CKD-EPI 2021 equation (race-free)
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Frequently Asked Questions
What is the Glomerulonephritis Evaluation (KDIGO 2021)?
The Glomerulonephritis Evaluation (KDIGO 2021) is a diagnostic clinical algorithm for Nephrology. It provides a structured decision tree to guide clinical decision-making, based on KDIGO 2021 Clinical Practice Guideline for the Management of Glomerular Diseases (with KDIGO 2024 Lupus Nephritis, KDIGO 2024 ANCA Vasculitis and KDIGO 2025 IgAN/IgAV chapter updates).
What guideline is the Glomerulonephritis Evaluation (KDIGO 2021) based on?
This algorithm is based on KDIGO 2021 Clinical Practice Guideline for the Management of Glomerular Diseases (with KDIGO 2024 Lupus Nephritis, KDIGO 2024 ANCA Vasculitis and KDIGO 2025 IgAN/IgAV chapter updates) (DOI: 10.1016/j.kint.2021.05.021).
What are the limitations of the Glomerulonephritis Evaluation (KDIGO 2021)?
Known limitations include: Adults only. Children with nephrotic syndrome: use the KDIGO 2025 paediatric guideline (glucocorticoids usually without biopsy).; Disease-specific treatment lines are summaries; doses and regimens must come from the current KDIGO chapter and a nephrologist.; Antithrombotic stop times before biopsy follow local protocol and product information.; Does not cover all glomerular diseases (for example C3 glomerulopathy, monoclonal gammopathy, infection-related GN) in detail.. Individual patient factors may require deviation from these recommendations.
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