Understanding the Glomerular Basement Membrane Antibodies blood test

The Glomerular Basement Membrane Antibodies blood test measures antibodies directed against the glomerular basement membrane (GBM), a critical structural component of the kidneys’ filtration units (glomeruli). These antibodies can cause rapid and severe kidney damage when the immune system mistakenly attacks this tissue.

Anti-GBM antibodies are most commonly associated with anti-glomerular basement membrane disease, also known as Goodpasture’s disease, an autoimmune condition that can affect both the kidneys and the lungs. In the lungs, the same antibodies may target basement membranes in the alveoli, leading to bleeding in the airways.

This test is considered urgent and high-importance when clinical features suggest rapidly progressive kidney disease or combined kidney–lung involvement.

When a Glomerular Basement Membrane Antibodies test is recommended

This test is recommended when there is suspicion of rapidly progressive glomerulonephritis or autoimmune disease affecting the kidneys and lungs. Early diagnosis is critical, as prompt treatment can significantly improve outcomes.

Testing may be appropriate if you:

• Have rapidly worsening kidney function
• Have blood or protein detected in urine
• Experience coughing up blood (haemoptysis)
• Have unexplained anaemia with lung symptoms
• Have acute kidney injury of unclear cause
• Are being assessed for suspected Goodpasture’s disease
• Have abnormal kidney imaging or biopsy findings
• Require urgent autoimmune kidney investigation

Benefits of the Glomerular Basement Membrane Antibodies test

• Supports early diagnosis of anti-GBM disease
  Identifies a serious but treatable autoimmune condition.
• Guides urgent clinical management
  Helps prioritise rapid treatment.
• Assesses kidney and lung autoimmune involvement
  Relevant in combined organ disease.
• Differentiates causes of rapidly progressive kidney failure
  Helps distinguish from other autoimmune conditions.
• High clinical specificity
  Strongly associated with anti-GBM disease when positive.
• Simple blood test despite complex condition
  Requires only a blood sample.
• Essential in nephrology assessment
  Widely used in specialist kidney care.
• Provides actionable diagnostic information
  Influences immediate treatment decisions.

How the test is carried out

We offer two convenient UK-wide testing options:

Clinic-based blood testing

• Choose your nearest UK clinic
• A healthcare professional collects a blood sample
• The sample is analysed in a certified laboratory
• Results are issued once testing is complete

Home or hotel blood collection (+£60)

• A qualified phlebotomist visits your home, workplace, or hotel
• Blood is collected at a time convenient for you
• No clinic visit required
• Available nationwide across the UK

Note: In suspected acute cases, urgent hospital assessment is advised even if testing is arranged privately.

Understanding your Glomerular Basement Membrane Antibodies results

Negative result

No anti-glomerular basement membrane antibodies detected. This suggests anti-GBM disease is unlikely at the time of testing.

Typical UK interpretation:

• Negative / Within reference range

Further testing may still be required if clinical suspicion remains high.

Positive result

The presence of anti-GBM antibodies strongly suggests anti-glomerular basement membrane disease.

Typical UK interpretation:

• Positive / Above reference range

Urgent nephrology and respiratory assessment is usually required.

Borderline result

A borderline result indicates antibody levels close to the threshold.

Typical UK interpretation:

• Equivocal

Repeat testing and specialist input may be recommended.