How is ANCA-associated vasculitis (AAV) diagnosed?

Successful diagnosis of AAV requires a very careful and systematic approach.1 The rarity and complexity of AAV means that people may have often seen multiple different doctors, and it can take a few months or sometimes years before they are diagnosed.1,2 For 1 in 3 people, it may take more than 6 months to receive their diagnosis.1

If you think you suffer from AAV but have not yet been diagnosed, it may help to be aware of potential symptoms and discuss them with your doctors to see if this will speed up diagnosis.1 Whatever you’re going through, there is no need to feel embarrassed of talking about it with your doctors. They will be used to discussing a wide range of health issues – and telling them about everything you are experiencing may be very useful in helping them to understand your disease.

Jeremy - MPA patient, UK

Jeremy - MPA patient, UK

What tests can be done to check for ANCA-associated vasculitis (AAV)?

Typically, your doctors will do a combination of tests and consider your medical history (your symptoms and what has happened to you) before diagnosing AAV. The clue that often leads to successful diagnosis is when multiple blood vessels in different organs are affected, leading to a variety of symptoms.


Blood tests

Urine tests

Imaging procedures

Biopsy (also called histological examination)

ANCA tests

Testing for ANCA autoantibodies in the blood helps in diagnosing 3 types of AAV – GPA, MPA and EGPA. About 8 in 10 people with GPA and MPA, and around 4 in 10 people with EGPA have detectable levels of ANCA.1 To look for ANCA in your blood, your doctors will first do a blood test, which will then be examined in a laboratory

While these tests are very useful, it is important to be aware that ANCA can also be found in people with other diseases such as chronic infections. In addition, some people with GPA or MPA do not have detectable levels of ANCA and their doctor will make a diagnosis based on the clinical picture (an assessment of all test results and symptom information).

 

Learn more about the
importance of ANCA

Inflammatory markers

Signs of inflammation (known as inflammatory markers) can usually be detected in the blood. Your doctors will usually look for these by measuring your blood cell sedimentation rate (which shows how fast the particles of your blood move in a test tube) and your level of C-reactive protein (or CRP – a type of protein that the liver produces in higher quantities when inflammation occurs).

Although the results of these tests can indicate your body is inflamed, they do not show which type of inflammation you have, so on their own, they are not sufficient for your doctors to diagnose AAV.

Kidney function

If your doctors suspect you may have kidney disease, they will investigate how well your kidneys are working by doing a blood test. This will typically look at your levels of creatinine (the main breakdown of protein in the muscles) and urea (the main breakdown product of proteins in the urine). Higher than usual levels of either can indicate that your kidneys are not eliminating them correctly after use, and that your kidney function may be impaired.

It is important for urine to be examined regularly so that small changes in urea and creatinine can be detected as soon as possible and any kidney damage can be minimised.

 

How may my AAV treatment be affected by other medical conditions?

If you have comorbidities (other diseases or conditions as well as AAV), your doctor may adjust the dose of some treatments, and/or monitor you more closely for a period of time. It may help to discuss what side-effects are associated potentially with your treatment as well as with other conditions, so you can distinguish these from signs that show your AAV is active and spot any potential AAV relapses as quickly as possible.1

AAV Patient Maresa – GPA & Kai (carer), Germany

How will my ANCA test results help my doctor understand my ANCA-associated vasculitis?

Jeremy - MPA patient, UK

There are two different ANCA autoantibodies that develop in people with AAV. These develop to two different proteins: proteinase 3 (PR3) or myeloperoxidase (MPO).1

PR3 and MPO are normally found inside neutrophils but if they appear outside, the ANCA can bind to them and activate the neutrophils, leading to damage.1 A blood test is used to see if one of these autoantibodies is present in your blood. This is the key test that your doctor will do to see if you have AAV.2,3

Why is testing for PR3 and MPO important?

Finding out whether the ANCA autoantibodies bind onto PR3 or MPO can help your doctors understand more about the possible outcome of your disease, and how likely you are to experience relapses.2 It may also help them to decide which treatment will be most suitable for you.3

Maresa – GPA & Kai (carer), Germany

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ANCA tests

Testing for ANCA autoantibodies in the blood helps in diagnosing 3 types of AAV – GPA, MPA and EGPA. About 8 in 10 people with GPA and MPA, and around 4 in 10 people with EGPA have detectable levels of ANCA.1 To look for ANCA in your blood, your doctors will first do a blood test, which will then be examined in a laboratory

While these tests are very useful, it is important to be aware that ANCA can also be found in people with other diseases such as chronic infections. In addition, some people with GPA or MPA do not have detectable levels of ANCA and their doctor will make a diagnosis based on the clinical picture (an assessment of all test results and symptom information).

 

Learn more about the
importance of ANCA

Inflammatory markers

Signs of inflammation (known as inflammatory markers) can usually be detected in the blood. Your doctors will usually look for these by measuring your blood cell lowering rate (which shows how fast the solid parts of your blood move in a test tube) and your level of C-Reactive protein (or CRP – a type of protein that the liver produces in higher quantities when inflammation occurs).

Although the results of these tests can indicate your body is inflamed, they do not show which type of inflammation you have, so on their own, they are not sufficient for your doctors to diagnose AAV.

Kidney function

If your doctors suspect you may have kidney disease, they will investigate how well your kidneys are working by doing a blood test. This will typically look at your levels of creatinine (which supplies muscles with energy) and urea (the main breakdown product of proteins). Higher than usual levels of either can indicate that your kidneys are not eliminating them correctly after use, and that your kidney function may be impaired.

It is important for urine to be examined regularly so that small changes in urea and creatinine can be detected as soon as possible and any kidney damage can be minimised.

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Urine tests

Urine tests are the easiest way to see whether a vasculitis-related inflammation is present in the kidneys. The urine is typically examined for red blood cells and protein.

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Imaging procedures

Imaging allows healthcare professionals to scan the inside of your body so they can check which areas are affected by AAV. Examples of imaging procedures you may experience include chest X-rays and/or CT or MRI scans, bronchoscopy (looking into airways/lungs with a camera) and sinus endoscopies (also using a small camera).

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Biopsy (also called histological examination)

This is a procedure where a small piece of tissue is removed (for example, from your kidney, lung, sinus or skin) for examination under a microscope. This can help to confirm your diagnosis and/or show whether AAV has spread to these areas. The biopsy will assist your doctor in deciding what treatment is best for you.

What to expect on the day of my biopsy

  • When you arrive at the hospital you may need to have a blood test

  • You might feel a small pushing sensation as the biopsy is taken

  • After the biopsy you may need to go for a scan

  • You may experience bruising and a dull ache in the general area of the biopsy

  • Most patients go home on the same day – however, depending on where your biopsy is taken from you may need some bed rest and your doctor will advise you on this

Tips on having a biopsy

  • Make sure to let your doctor know of any medications that you are taking

  • Regularly check your biopsy site and contact your doctor immediately if you notice any visible symptoms or changes in how you feel

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How may my AAV treatment be affected by other medical conditions?

If you have comorbidities (other diseases or conditions as well as AAV), your doctor may adjust the dose of some treatments, and/or monitor you more closely for a period of time. It may help to discuss what side effects are associated with your other conditions, so you can distinguish these from signs that show your AAV is active and spot any potential AAV relapses as quickly as possible.1

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