What initial investigations should I perform for a patient presenting with suspected glomerulonephritis?

Guideline-aligned answer with reasoning, red flags and references. Clinically reviewed by Dr Kola Tytler MBBS CertHE MBA MRCGP.

Posted: 16 August 2025Updated: 16 August 2025 Guideline-Aligned (High Confidence) Clinically Reviewed
Dr Kola Tytler MBBS CertHE MBA MRCGPClinical Lead • iatroX

For a patient presenting with suspected glomerulonephritis, initial investigations should focus on assessing kidney function and identifying key markers such as proteinuria and haematuria.

  • Urine Tests:
    • Perform a urine albumin:creatinine ratio (ACR) for the initial detection of proteinuria . A confirmed ACR of 3 mg/mmol or more is considered clinically important .
    • Use reagent strips to test for haematuria, evaluating further for results of 1+ or higher .
    • If persistent haematuria is present alongside an ACR of 30 mg/mmol or more, a urinary tract infection (UTI) should be excluded ,.
  • Blood Tests:
    • Measure serum creatinine to estimate the glomerular filtration rate (eGFR) . If an eGFR result of less than 60 ml/min/1.73 m2 is found in an adult not previously tested, repeat the test within 2 weeks to confirm .
    • In adults with acute illness, investigate for acute kidney injury by measuring serum creatinine if symptoms or signs of nephritis (such as oedema or haematuria) are present .
  • Imaging:
    • Consider offering a renal ultrasound scan if there is visible or persistent invisible haematuria, or if the eGFR is less than 30 ml/min/1.73 m2 (GFR category G4 or G5) .

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