According to a publication from ANCA Vasculitis News, a sizable number of people who do not have ANCA-associated vasculitis could falsely test positive due to the presence of the associated antibody in their systems.
About ANCA-Associated Vasculitis
ANCA-associated vasculitis (or AAV) is a group of inherited autoimmune diseases. These are diseases where a patient’s own immune system malfunctions, and starts to attack healthy tissues as if they were foreign objects. AAV is one such condition – when a patient’s neutrophils (the most abundant type of white blood cell) attack small blood vessels, they start to break them down. This can critically damage major organs like the heart, lungs, or kidneys.
ANCA (from the name) is a type of autoantibody that mistakenly targets proteins found in white blood cells. In individuals with AAV, there could be an excessive amount of ANCA antibodies.
The underlying cause of AAV is not yet fully understood. Until a better option becomes available the condition is treated with some common autoimmune drugs like cyclophosphamide or rituximab.
Antibodies Are a Hint, Not an Answer
Individuals being screened for AAV typically have their ANCA levels checked. This involves determining if there is a presence of ANCA antibodies, and if one exists, where and in what form.
Other methods of detecting ANCA are being developed, but currently antibody testing is one of the most common tools in aiding AAV diagnosis.
According to research from Israel, however, some patients who test positive for certain types of ANCA antibody have been diagnosed with conditions other than AAV.
The Israeli research involved 113 people who had previously tested positive for ANCA antibodies. At the end of the study, it was found that only a mild 39.8% of respondents had evidence of AAV.
In other words, most people who tested positive for ANCA didn’t have the condition they were ultimately being screened for. Researchers did note, however, that high levels of ANCA antibodies were more common in the respondents with AAV than in those without.
“These findings underscore the fact that ANCA test results should be interpreted with caution,” the research team noted. They also reasoned that more sensitive forms of testing might be required to aid in accurate diagnosis.
Often we’re so focused on “solving” a disease we forget our methods may need improvement as well. What role is there for trial and error in modern medicine, if there is one? Share your thoughts with Patient Worthy!
