Why is ANCA High? Causes, Symptoms, and What to Do

Antineutrophil cytoplasmic antibodies (ANCA) are a type of antibody that can mistakenly target and attack the body's own cells, leading to inflammation. A high level of ANCA is a marker that can indicate certain autoimmune conditions, particularly ANCA-associated vasculitis. Understanding why ANCA levels are high, what symptoms may arise, and when to seek medical advice can help in managing your health effectively.

What is ANCA?

ANCA stands for antineutrophil cytoplasmic antibodies. These are autoantibodies, which means they are antibodies that mistakenly target and attack the body's own tissues. ANCA are primarily associated with autoimmune conditions that affect blood vessels, known as vasculitis. The presence of ANCA is detected through a blood test, and results are measured in units per milliliter (U/mL).

Why are ANCA levels high?

High levels of ANCA are most commonly associated with a group of diseases called ANCA-associated vasculitis. This includes conditions like granulomatosis with polyangiitis and microscopic polyangiitis. These conditions cause inflammation of blood vessels, which can lead to damage in organs such as the kidneys and lungs. While a positive ANCA test supports the diagnosis of these conditions, it is usually read together with other markers of kidney function and inflammation.

Symptoms of high ANCA levels

Symptoms of conditions associated with high ANCA levels can vary but often include fatigue, fever, and weight loss. More specific symptoms depend on which organs are affected. For example, if the lungs are involved, you might experience coughing or shortness of breath. If the kidneys are affected, there may be blood in the urine or swelling in the legs.

How to interpret ANCA test results

A normal ANCA test result is considered negative and is less than 20 U/mL. A positive result, which is greater than or equal to 20 U/mL, may support a diagnosis of ANCA-associated vasculitis, especially when accompanied by abnormalities in kidney function or inflammation markers. It is important to discuss your test results with a healthcare professional to understand what they mean for you.

What to do if ANCA levels are high

If your ANCA levels are high, it is crucial to follow up with your healthcare provider. They will likely perform additional tests to assess kidney function and check for signs of inflammation or other related conditions. Treatment plans may include medications to suppress the immune system and reduce inflammation.

Frequently asked questions

What does a positive ANCA test mean?
A positive ANCA test indicates that the levels are 20 U/mL or higher. This result may suggest the presence of ANCA-associated vasculitis and should be interpreted alongside other clinical findings.

Can infections cause high ANCA levels?
Infections are not commonly associated with high ANCA levels. ANCA is more typically related to autoimmune conditions, although some infections might transiently affect these levels.

Are there other tests to confirm ANCA-associated vasculitis?
Yes, doctors may order additional tests, such as kidney function tests and imaging studies, to confirm the diagnosis and assess the extent of organ involvement.

When to see a doctor

If you have received a positive ANCA test result or are experiencing symptoms such as unexplained fatigue, fever, or signs of organ involvement like blood in urine or shortness of breath, it is important to consult a healthcare provider. They can help determine the cause of your symptoms and guide you through further testing and treatment options.

Decisions about your health should always be made in consultation with your healthcare provider.