Evidence‐based guidelines for the use of immunologic tests: Antinuclear antibody testing

This article is part of a series on immunologic testing guidelines. The series introduction, published in this issue, outlines the full methodology for obtaining data, grading the literature, combining the information from multiple sources, and developing recommendations. Briefly, MEDLINE and Healthstar were searched using a variety of search terms, and all relevant available literature was reviewed. All articles were critically reviewed using published standards for studies of diagnostic tests. Test use was categorized as primarily diagnostic or prognostic (which also included monitoring). Information was extracted from each article to allow for calculation of a weighted average for sensitivity and specificity; likelihood ratios (LRs) were then derived from these values (positive LR sensitivity / [1-specificity]; negative LR [1-sensitivity] / specificity). Recommendations for use of tests were based on the LRs, where a test was considered to be “very useful” for a given disease if the weighted average positive LR was 5 or negative LR was 0.2. A test was considered “useful” if the weighted average positive LR was 2 and 5 or negative LR was 0.2 and 0.5. A test was considered “not useful” if the positive LR was 2 or the negative LR was 0.5.