Article Text
Statistics from Altmetric.com
Antinuclear antibodies (ANA) are important laboratory markers for the diagnosis and classification of systemic lupus erythematosus (SLE). In the 2019 European League Against Rheumatism (EULAR)/American College of Rheumatology (ACR) classification criteria for SLE, ANA with titre ≥1:80 are an entry criterion.1
Even though ANA 1:80 are highly sensitive for SLE, they have a low specificity. This has recently been reinforced by Aringer et al 2 who analysed the performance of the individual items included in the 2019 EULAR/ACR classification criteria for SLE on a large group of patients with SLE (n=1197) and non-SLE disease controls (n=1074), including patients with other connective tissue diseases (two-thirds of the controls). In this study, ANA with titre ≥1:80 were highly sensitive (99.5%), but only 19.4% specific for SLE.2 As ANA are an entry criterion for the 2019 EULAR/ACR classification criteria, the low specificity of ANA for SLE does not affect the specificity of the 2019 SLE classification criteria. An important item that conferred specificity to the 2019 SLE classification was the attribution rule.2 The authors stressed that ANA are a useful screening test, but not specific and that the classification criteria should not be used as diagnostic criteria.2
As ANA are employed in the context of both classification and diagnosis, it is …
Footnotes
Handling editor Josef S Smolen
Contributors XB drafted the manuscript. All authors discussed the content and contributed to the final manuscript.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests None declared.
Patient and public involvement Patients and/or the public were not involved in the design, or conduct, or reporting, or dissemination plans of this research.
Provenance and peer review Commissioned; internally peer reviewed.