Pitfalls of Autoimmune Serologic Testing: A Practical Summary for Primary Care Nurse Practitioners
Pitfalls of Autoimmune Serologic Testing A Practical Summary for Primary Care Nurse Practitioners Based on: Bellocchi C, Beretta L, Montano N. European Journal of Internal Medicine (2026) ⚠️ CORE PRINCIPLE Autoimmune serologic markers are a supporting tool—not a standalone diagnostic test. Always interpret results within the clinical context: history, physical examination, and symptom pattern. Testing should be driven by clinical suspicion, not used for screening in the general population. 1. ANA Testing: Where It All Starts Antinuclear antibodies (ANA) by indirect immunofluorescence (IIF) on HEp-2 cells remain the first-line screening test when a connective tissue disease (CTD) is suspected. Key Points for Practice • Titer ≥1:160 is the threshold for a clinically meaningful positive in most contexts. • For SLE specifically, ANA ≥1:80 meets the en...