This panel is a focused set of tests used to investigate autoimmune conditions, diseases in which the immune system mistakenly attacks the body’s own tissues. The starting point is an ANA (antinuclear antibody) screen, which looks broadly for antibodies that bind to cell nuclei. If this screen is positive, the lab automatically checks for more specific autoantibodies, each tied to certain diseases.
- dsDNA antibody: Targets DNA itself, strongly linked to systemic lupus erythematosus (SLE), especially when the disease affects the kidneys.
- Smith (Sm) antibody: Highly specific for lupus, though less common. Its presence supports the diagnosis even if other markers are borderline.
- Scl-70 (topoisomerase I) antibody: Often found in diffuse systemic sclerosis (scleroderma), particularly with lung and skin involvement.
- Jo-1 antibody: A marker for polymyositis and dermatomyositis, especially when there is associated lung inflammation (interstitial lung disease).
- SS-A (Ro) and SS-B (La) antibodies: Hallmarks of Sjögren’s syndrome, a condition that damages tear and salivary glands, but also seen in lupus and other connective tissue diseases.
- RNP antibody: Found in mixed connective tissue disease (MCTD), where features of lupus, scleroderma, and polymyositis overlap.
- Chromatin antibody: Can be present in lupus and other autoimmune conditions; it reflects immune attack against the proteins that help package DNA.
- Centromere B antibody: Associated with limited cutaneous systemic sclerosis (formerly called CREST syndrome), a scleroderma variant that progresses more slowly but can affect blood vessels and the lungs.
The value of this panel is that it does not just show whether autoimmunity is present but also helps narrow down which condition is most likely. Because many autoimmune diseases share symptoms, fatigue, joint pain, rashes, dry eyes and mouth, these antibodies serve as fingerprints, guiding diagnosis and treatment. That said, a positive test does not always equal disease; low levels can appear in healthy people, especially with age. Interpretation always depends on the full clinical picture.
