Autoimmune Antibody Profile Evaluator

Academic Diagnostic & Induction Therapy Pathway
📈 Resident Gateway: Use semi-quantitative inputs (+ to ++++). The engine cross-references serology with clinical signs to map ACR/EULAR 2019 criteria, preventing overtreatment of transient line-blot false positives.

1. Primary Diagnostic Anchors

2. Extended ENA & Advanced Markers (Immunoblot / Line-blot)

3. Disease Activity & Vasculitis Anchors

4. Required Clinical Correlation (Mandatory for diagnostic mapping)

Academic Ward Pearls & The Indian Context

⚠ The Great Indian Mimics: Before You Diagnose SLE/RA

Never diagnose an autoimmune disease in India without strictly ruling out these endemic mimics first. Avoid empirical steroids.
The MimicClinical PresentationAutoantibody False Positives
Kikuchi-Fujimoto DiseaseYoung female, fever, cervical lymphadenopathy, cytopenias. Perfectly mimics SLE flare.Low-titre ANA. (Requires lymph node biopsy to differentiate).
Leprosy (Hansen's)Polyarthritis, neuropathy, skin lesions. Type 2 reactions mimic severe vasculitis.ANA, RF, and sometimes ANCA can be transiently positive.
TuberculosisChronic fever, weight loss, cavitating lung lesions (mimics GPA/Wegener's), Poncet's polyarthritis.RF, c-ANCA (low titre).
Chikungunya / DengueSevere symmetric polyarthritis, rash, thrombocytopenia.RF, Low-titre ANA.

💡 ENA Interpretation Mnemonic

To remember the primary associations of Extractable Nuclear Antigens:

  • Ro/La = Dry: Sjögren's (dry eyes, dry mouth).
  • Sm = SLE: Highly specific for Systemic Lupus Erythematosus.
  • Scl = Stone: Scleroderma (skin thickening, fibrosis).
  • Jo/SRP = Joints & Muscle: Inflammatory Myopathies.

◆ The Line-Blot Trap: Interpreting Weak Positives (+)

Extractable Nuclear Antigen (ENA) panels are frequently run on Immunoblot (Line-Blot) strips. A weak positive (+ or ++) line is notoriously prone to false positives due to cross-reactivity with viral/bacterial antigens. A strong positive (+++ or ++++) carries much higher diagnostic specificity. Always correlate a weak ENA with the clinical phenotype; do not treat the paper.

✘ STATIC MARKERS (Do Not Repeat)
  • ANA (IFA)
  • Anti-Sm, Anti-Ro/La
  • Anti-U1 RNP, Anti-Scl-70
These establish the diagnosis. Titres do not reliably correlate with disease activity.
✔ DYNAMIC MARKERS (Monitor Serially)
  • Anti-dsDNA Titre
  • Complement (C3 & C4)
  • ANCA Titres (in selected cases)
Rising dsDNA + falling C3/C4 predicts an impending Lupus Nephritis flare.

◆ The Diagnostic Anchor: ANA IFA Patterns

The Indian Rheumatology Association mandates IFA on HEp-2 cells. ELISA should not be used for primary ANA screening. The pattern guides your ENA panel interpretation.

ANA Pattern (IFA)Primary AssociationsSpecific ENA to Expect
HomogeneousSLE, Drug-induced LupusdsDNA, Histone, Nucleosome
SpeckledMCTD, Sjögren's, SLEU1-RNP, Sm, Ro (SSA), La (SSB)
NucleolarSystemic Sclerosis (Diffuse)Scl-70, PM-Scl, Fibrillarin
CentromereLimited Scleroderma (CREST)CENP-A, CENP-B
CytoplasmicMyositis, PBC, Neuro-SLEJo-1, AMA-M2, Ribosomal P
Abbreviations: ACR (American College of Rheumatology) · EULAR (European Alliance of Associations for Rheumatology) · ANA (Antinuclear Antibody) · IFA (Immunofluorescence Assay) · ENA (Extractable Nuclear Antigen) · dsDNA (Double-stranded DNA) · RNP (Ribonucleoprotein) · SLE (Systemic Lupus Erythematosus) · MCTD (Mixed Connective Tissue Disease) · ILD (Interstitial Lung Disease) · GPA (Granulomatosis with Polyangiitis) · MPA (Microscopic Polyangiitis) · GBM (Glomerular Basement Membrane) · MMF (Mycophenolate Mofetil) · HCQ (Hydroxychloroquine) · DMARD (Disease-Modifying Antirheumatic Drug)
Algorithm References & Evidence Base
  1. Aringer M, et al. 2019 European League Against Rheumatism/American College of Rheumatology Classification Criteria for Systemic Lupus Erythematosus. Arthritis Rheumatol. 2019;71(9):1400-1412.
  2. Misra DP, et al. Indian Rheumatology Association consensus statement on antinuclear antibody testing. Indian J Rheumatol. 2023.
  3. van den Hoogen F, et al. 2013 classification criteria for systemic sclerosis: an American College of Rheumatology/European League against Rheumatism collaborative initiative. Ann Rheum Dis. 2013;72(11):1747-1755.
  4. Lundberg IE, et al. 2017 European League Against Rheumatism/American College of Rheumatology classification criteria for adult and juvenile idiopathic inflammatory myopathies and their major subgroups. Ann Rheum Dis. 2017;76(12):1955-1964.
How to Cite This Tool

AMA Style:
Umakanth S. Autoimmune Antibody Profile Evaluator. MEDiscuss. Published 2026. Accessed .

Vancouver Style:
Umakanth S. Autoimmune Antibody Profile Evaluator [Internet]. MEDiscuss.org; 2026 [cited ]. Available from:

⚠ Disclaimer: This decision-support system is intended for healthcare professionals. It does not substitute clinical judgment. These algorithms are evidence-based, but medical knowledge evolves continuously. The treating physician retains absolute responsibility for all diagnostic, dosing, and therapeutic decisions. Always verify outputs against current institutional protocols and individual patient contexts.
© 2026 MEDiscuss.org. All rights reserved. This CDSS Module was conceptualised, designed and developed by
Dr. Shashikiran Umakanth.Provided free of charge for clinical use. Unauthorised reproduction or redistribution is strictly prohibited.
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