Harmonization of Autoimmune diagnostics with Antinuclear Antibody Testing Algorithm: Approach of Appropriateness and Clinical Relevance

l imiting inappropriate test requests and identifying a balance between available economic resources and growing health needs is crucial for health care services today. In this context, harmonizing testing algorithms is a goal. As such, the clinical laboratory plays a critical role to help interpret clinical presentations that are often misleading in these pathologies. Recent advances in diagnostic technologies for autoimmune diseases have had a vital impact on the diagnostic approach to these pathologies. The presence of antinuclear antibodies (ANA) in the serum, anti-extractable nuclear antigens (ENA) and anti-double stranded DNA (dsDNA) is one of the diagnostic criteria for autoimmune rheumatic disease. The test request for these assays has grown exponentially, due to increasing knowledge of the pathogenetic and diagnostic value of autoantibodies in autoimmune diseases and the inappropriate use of laboratory diagnostics. The latter problem is not precisely defined as yet, and is mainly a consequence of several factors, including inadequate collaboration or audit between physicians and laboratory personnel, availability of different techniques and methodologies in laboratory practice for assessing the same marker, and lack of a uniform terminology and diagnostic algorithms when performing autoantibody testing. Furthermore, a reduction in the number of clinically inappropriate requests and the establishment of a reasonable balance between available economic resources and increasing needs is a principal target of health care services worldwide. To improve the appropriateness of the test requests in autoantibody testing, reliable and universally accepted diagnostic algorithms need to be defined and implemented; these algorithms should have been developed using the available guidelines found in the current scientific literature and should be shared by all physicians working in clinical immunology. The most appropriate strategy for requesting autoimmune rheumatic disease laboratory testing should encompass selective criteria; it should begin from a clinical suspicion, followed by a logical succession of analyses performed with sensitive tests at an early stage and specific tests for confirmation. In view of its solid diagnostic performance, the ANA test has been proposed by several authors as a first-level test in the laboratory diagnosis of autoimmune rheumatic diseases, whereas tests for antibodies to specific nuclear antigens can only be detected when ANA screening is positive or if the patient has clear signs and symptoms suggesting a systemic rheumatic disease (second-level tests).