Systemic Lupus Erythematosus: Investigations

Key points

• 99% are ANA positive
• 20% are rheumatoid factor positive
• anti-dsDNA: highly specific (> 99%), but less sensitive (70%)
• anti-Smith: most specific (> 99%), sensitivity (30%)
• also: anti-U1 RNP, SS-A (anti-Ro) and SS-B (anti-La) Monitoring