A general and over-simplified answer is: no. This answer is based on the statistical analysis of large groups of patients followed prospectively in clinical trials. The results from these studies have led to the general opinion held by vasculitis experts that treatment decisions should not be made based on changes in ANCA levels alone.
There are some patients, however, for whom ANCA levels track the disease activity very well. In these patients, ANCA increases do predict relapses. To know how ANCA levels relate to disease activity in individual patients, their ANCA levels need to be monitored over time.
It should also be noted that there are different ways of measuring ANCA levels. To follow serial ANCA levels, they need to be measured by the same method to be able to make comparisons.(Click the back button in your browser to go back to the FAQ page.)