From the Guidelines
A positive Antinuclear Antibody (ANA) test requires careful follow-up testing and clinical correlation before initiating treatment, with the next steps including ordering specific autoantibody panels and referral to a rheumatologist for proper evaluation. The patient's symptoms should guide the selection of additional autoantibody tests, such as anti-dsDNA, anti-Smith, anti-SSA/SSB, anti-RNP, anti-Scl-70, and anti-centromere antibodies 1.
Follow-up Testing
- Complete blood count, comprehensive metabolic panel, inflammatory markers (ESR, CRP), urinalysis, and complement levels (C3, C4) should also be obtained to assess the patient's overall health and potential organ involvement 1.
- A double-screening strategy using a last-generation SPA in the first place and, subsequently, the CLIFT as the confirmation test is recommended for anti-dsDNA testing 1.
- If the CLIFT assay is positive, but the SPA is negative, the result should be explained, and the laboratory may recommend repeating the anti-dsDNA assays in a new sample 1.
Clinical Correlation and Referral
- Referral to a rheumatologist is essential for proper evaluation, as a positive ANA alone is insufficient for diagnosis of autoimmune disease 1.
- The pattern and titer of ANA can provide clues to specific autoimmune conditions, with high titers (≥1:160) being more clinically significant than low titers 1.
- Treatment depends on the specific diagnosis established through these additional tests and clinical assessment, with examples including hydroxychloroquine for systemic lupus erythematosus and methotrexate for rheumatoid arthritis 1.
Interpretation of Results
- The laboratory should specify each method used for ANA detection and report the results obtained by each method separately if multiple methods are used 1.
- The results should be interpreted in clinical context, considering the patient's symptoms, medical history, and potential underlying conditions that may cause a positive ANA test, such as certain medications, infections, or malignancies 1.
From the Research
Follow-up Testing for Positive ANA
- A positive Antinuclear Antibody (ANA) test result indicates the presence of autoantibodies in the blood, which can be associated with various autoimmune diseases, including Systemic Lupus Erythematosus (SLE) 2, 3.
- The next steps for follow-up testing and treatment in a patient with a positive ANA test result may include:
- Further testing to determine the specific type and level of autoantibodies present, such as anti-double-stranded DNA (anti-dsDNA) and anti-extractable nuclear antigen (ENA) antibodies 2, 4.
- Evaluation of clinical symptoms and medical history to determine the likelihood of an autoimmune disease diagnosis 5, 3.
- Consideration of other laboratory tests, such as complete blood count, blood chemistry, and urinalysis, to assess overall health and detect any potential organ damage 6.
Treatment and Management
- Treatment and management of patients with a positive ANA test result will depend on the underlying diagnosis and severity of symptoms 4, 6.
- For patients with SLE or other autoimmune diseases, treatment may include immunosuppressive medications, corticosteroids, and other therapies to manage symptoms and prevent disease progression 2, 3.
- Regular monitoring of autoantibody levels and clinical symptoms is essential to adjust treatment plans and prevent complications 4, 6.
Interpretation of ANA Test Results
- The interpretation of ANA test results requires consideration of the disease context, antibody level, and technique used for detection 6.
- A positive ANA test result should be interpreted in conjunction with clinical symptoms and other laboratory test results to determine the likelihood of an autoimmune disease diagnosis 5, 3.
- The use of titre-specific information, such as likelihood ratios, can help guide the interpretation of ANA test results and inform treatment decisions 6.