Antiglomerular Basement Membrane Antibody Test- Why am I having this test?
This test is used to determine the presence of antibodies to the glomerular basement membrane in the kidneys and lungs. This membrane filters extra fluid and waste from the blood.
The antibodies cause inflammation of the kidneys (glomerulonephritis). They also cause bleeding in the lungs. The presence of antibodies along with lung and kidney problems may be a sign of an autoimmune disease called Goodpasture syndrome.
The antibody levels can also be used to measure the body’s response to therapy.
What is being tested?
This test measures the presence of antibodies to the glomerular basement membrane in the kidneys or lungs.
What kind of sample is taken?
This test can be conducted by collecting one of the following samples:
- Tissue. This is usually collected by taking a piece of tissue from a lung or kidney (biopsy).
- Blood. This is usually collected by inserting a needle into a blood vessel.
How do I prepare for this test?
Do noteat or drink anything for 8 hours before the test or as directed by your health care provider. You may drink water.
How are the results reported?
Your results may be reported in different ways depending on which type of sample is collected. Typically, the results are reported as negative, borderline, or positive.
Tissue
- Negative: No antibodies are found in the sample.
Blood EIA (enzyme immunoassay)
- Negative: Less than 20 units.
- Borderline: 20–100 units.
- Positive: Greater than 100 units.
What do the results mean?
- If your blood test results are borderline, your health care provider will consider all of your symptoms and test results. You may need further testing, including a lung or kidney biopsy.
- A
positive test result may indicate:
- Goodpasture syndrome. This is a condition in which the body’s defense (immune) system attacks the kidneys or lungs.
- Autoimmune glomerulonephritis. This is a condition in which the body’s immune system attacks the tiny blood vessels in the kidneys.
- Lupus. This is a condition that can affect the kidneys.
Talk with your health care provider about what your results mean.
Questions to ask your health care provider
Ask your health care provider, or the department that is doing the test:
- When will my results be ready?
- How will I get my results?
- What are my treatment options?
- What other tests do I need?
- What are my next steps?
Summary
- This test measures the presence of antibodies to the glomerular basement membrane in the kidneys or lungs.
- This test can be conducted by collecting either a tissue sample from a kidney or lung (biopsy) or a blood sample.
- A positive test result may indicate Goodpasture syndrome, autoimmune glomerulonephritis, or lupus.
