The ENA Panel is a group of blood tests that detect antibodies against extractable nuclear antigens. These antigens are proteins found in the nucleus of cells. The panel usually includes antibodies against the following specific antigens:
- Anti-Smith (Sm)
- Anti-RNP (Ribonucleoprotein)
- Anti-SSA (Ro)
- Anti-SSB (La)
- Anti-Scl-70 (Topoisomerase I)
- Anti-Jo-1 (Histidyl-tRNA synthetase)
- Anti-Centromere

The presence of these antibodies can help diagnose various autoimmune conditions, including systemic lupus erythematosus (SLE), Sjögren's syndrome, scleroderma, polymyositis, and dermatomyositis.

- **Positive Results**: Positive results may indicate the presence of an autoimmune disease, but they are not definitive on their own. They should be interpreted in the context of clinical symptoms and other diagnostic tests.
- **False Positives/Negatives**: Positive results can sometimes occur in healthy individuals or in those with other conditions. Conversely, negative results do not entirely rule out autoimmune disease.

- **Normal**: Generally, the normal range for ENA antibodies is negative. This means that no significant levels of these specific autoantibodies are detected in the blood.
- **Specifics**: Each antibody in the panel has its own normal range, which is usually reported as a qualitative result (e.g., positive/negative) rather than a quantitative measurement. Reference ranges may vary slightly between different laboratories.

- **Anti-Smith (Sm)**: Typically associated with systemic lupus erythematosus (SLE). Positive in a small percentage of SLE patients.
- **Anti-RNP**: Often associated with mixed connective tissue disease (MCTD) but can also be positive in other autoimmune diseases.
- **Anti-SSA (Ro)**: Commonly seen in Sjögren's syndrome and SLE.
- **Anti-SSB (La)**: Often found in Sjögren's syndrome and SLE.
- **Anti-Scl-70**: Associated with scleroderma.
- **Anti-Jo-1**: Found in polymyositis and dermatomyositis.
- **Anti-Centromere**: Linked to limited scleroderma (CREST syndrome).

- **Blood Sample**: The test requires a blood sample, usually drawn from a vein in your arm.