[Relevance assessment of requests for antineutrophil cytoplasmic antibodies detection: Retrospective study led in Bordeaux Hospital, France]

Abstract

Introduction: During year 2013, 5943 tests for antineutrophil cytoplasmic antibodies (ANCA) detection were performed in Bordeaux hospital, France. This seemed disproportionate, with regard to the low prevalence of ANCA-associated vasculitis (AAV). Our purpose was to evaluate the relevance of these requests.

Methods: Requests for detection of ANCA during 2013 were recorded, with their results. A sample of 501 requests was secondarily established. Relevance of requests was assessed independently by two reviewers. During year 2014, we developed strategies of information, in order to reduce the number of requests and increase their relevance.

Results: Only 17.8 % of the 5943 requests for detection of ANCA resulted in a positive test using indirect immunofluorescence (including 10.6 % of the requests with titles above 1/50). Using Luminex©, 9.7 % of the test of detection against antimyeloperoxidase or antiproteinase 3 antibodies were positive. Within the sample of 501 patients, only 28.7 % of the requests were relevant. A percentage of 40.2 of them weren't justified by a clinical affection typically associated with AAV. Exactly 15.9 of the requests were performed during systematic autoimmune screening. None of these requests could lead to the diagnosis of AAV. Combination of information procedures and use of a request form enabled a 19 % decrease of the number of requests. The percentage of requests without clinical justification also reduced from 40.2 % to 17.1 %. The reduction of the number of requests led to a 46,865 € saving.

Conclusion: The majority of the requests for detection of ANCA was not relevant and could not lead to the diagnosis of AAV. Simple solutions enabled a partial but significant improvement of their relevance.

Keywords: Antibodies; Anticorps anticytoplasmes des polynucléaires neutrophiles; Diagnostic techniques and procedures; Techniques et procédures diagnostiques; Vascularite; Vasculitis; antineutrophil cytoplasmic.