ANA Screening — High Sensitivity, Low Specificity
ANA is a broad first-line screen, not a lupus-specific test.
- ~95%: ANA sensitivity in SLE (placeholder summary stat)
- ~15%: Healthy population positive (placeholder summary stat)
- IFA HEp-2: Common method (placeholder summary stat)
- High: Negative predictive value (placeholder summary stat)
Why ANA is used as a screening test
Placeholder: ANA screening rules lupus out more than it rules it in.
Placeholder key insight about ANA screening sensitivity.
Titer Level and Immunofluorescence Pattern
Titer magnitude and staining pattern both shape interpretation.
- 1:80: Low positive cutoff (placeholder summary stat)
- ≥1:1280: High positive cutoff (placeholder summary stat)
- dsDNA/histone: Homogeneous pattern link (placeholder summary stat)
- ENA antigens: Speckled pattern link (placeholder summary stat)
How titer and pattern refine the differential
Placeholder: higher titers and homogeneous patterns favor lupus.
Placeholder key insight about titer/pattern significance.
Anti-dsDNA — A Specific Marker for Lupus
Anti-dsDNA antibodies are much more specific to SLE than ANA.
- ~95%: Anti-dsDNA specificity (placeholder summary stat)
- ~70%: Anti-dsDNA sensitivity (placeholder summary stat)
- Farr / ELISA: Common assay (placeholder summary stat)
- Nephritis: Associated organ risk (placeholder summary stat)
Why anti-dsDNA confirms the ANA screen
Placeholder: anti-dsDNA positivity strongly supports an SLE diagnosis.
Placeholder key insight about anti-dsDNA specificity.
Anti-dsDNA Fluctuation and Disease Activity
dsDNA titers often rise before or during a lupus flare.
- Moderate: Flare correlation strength (placeholder summary stat)
- Low C3/C4: Complement pairing (placeholder summary stat)
- Weeks: Lead time before flare (placeholder summary stat)
- Complement: Best paired marker (placeholder summary stat)
Using dsDNA trends to anticipate flares
Placeholder: rising dsDNA with falling complement signals activity.
Placeholder key insight about dsDNA-flare correlation.
Serial Testing for Longitudinal Disease Control
Repeated titers over time inform treatment adjustment decisions.
- 3 months: Typical retest interval (placeholder summary stat)
- 6 months: Stable disease interval (placeholder summary stat)
- Closer follow-up: Rising titer action (placeholder summary stat)
- C3/C4, UA: Key paired labs (placeholder summary stat)
Building a monitoring cadence around trends
Placeholder: serial trends outperform single-point measurements.
Placeholder key insight about serial monitoring strategy.