LAUSR

Pisetsky et al recently reported substantial variability between two antinuclear antibodies (ANA) indirect immunofluorescence (IIF) assays as well as one solid-phase assay (SPA) from different manufacturers in a study of a cross-sectional cohort of systemic lupus erythematosus (SLE) patients.1 This publication triggered several responses related to the performance of IIF for ANA detection.2–6 Bizzaro questioned whether ANA testing by IIF can be replaced by SPAs for the diagnosis of ANA-associated rheumatic disorders (AARD).7 On the basis of his experience and a literature review, he concluded that (1) overall screening by SPAs yields results that are at least comparable to the sensitivity of ANA-IIF results, (2) the performance of the assays depends on the disease being investigated and (3) the best diagnostic strategy seems to be the concomitant use of the two methods,7 which is in accord with previous suggestions.8 We hereby further illustrate that combining SPA with IIF adds value based on the data from a recently published study of 480 patients with AARD [SLE (n=119), primary Sjogren’s syndrome (SjS, n=65), systemic sclerosis (SSc, n=220), idiopathic inflammatory myopathies (IIM, n=50) and mixed connective tissue disease (n=56)] and 767 diseased controls.9 ANA detection was performed by automated IIF (NOVA View, Inova Diagnostics, San Diego, CA, …