Understanding Lab Tests for Autoimmune Diseases
Written by Private MD Labs Medical Writing Team • Last Updated: September 8, 2025
Autoimmune diseases occur when the body's immune system mistakenly attacks its own healthy tissues and organs. These conditions include rheumatoid arthritis, systemic lupus erythematosus, Sjögren's syndrome, and many others. Blood tests play a crucial role in diagnosing autoimmune diseases by detecting specific antibodies, measuring immune system activity, and identifying inflammation markers.
Top Recommended Test
IgG, IgA, Indirect Immunofluorescence
This test is fundamental for autoimmune disease diagnosis as it can detect autoantibodies commonly associated with conditions like lupus, Sjögren's syndrome, and rheumatoid arthritis. Positive indirect immunofluorescence results indicate the presence of antibodies attacking the body's own tissues. Additionally, elevated IgG levels may suggest an overactive immune response characteristic of autoimmune diseases.
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How Blood Tests Help Diagnose Autoimmune Diseases
Unlike conditions with visible symptoms, autoimmune diseases often require specialized blood tests to confirm diagnosis. These tests can detect autoantibodies (antibodies that attack the body's own tissues), measure immune cell populations, assess organ function, and identify inflammatory responses that characterize autoimmune conditions.
Other Relevant Tests
Lymphocyte Subset Panel 4 (CD4:CD8 Ratio Profile)
This test measures the ratio of CD4 to CD8 immune cells, which can be altered in autoimmune diseases. In conditions like rheumatoid arthritis or lupus, the CD4:CD8 ratio may be elevated due to an overactive immune response, resulting in an excess of CD4 cells that contribute to tissue damage.
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Aspartate Aminotransferase (AST/SGOT)
This liver enzyme test helps assess tissue damage that may occur in autoimmune diseases. Conditions like systemic lupus erythematosus or rheumatoid arthritis can increase AST levels due to inflammation and damage to various tissues, making it a valuable marker for monitoring disease activity.
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Herpes Simplex Virus 2 (IgG), Type-Specific Antibody
While primarily used to detect HSV-2 infection, abnormal levels of HSV-2 IgG antibodies can sometimes be observed in autoimmune diseases where the immune system mistakenly attacks the body's own tissues. This test may provide additional insight into immune system dysfunction, though the relationship requires further specific testing for confirmation.
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Rabies Vaccine Response End Point Titer
This test measures immune response to vaccination and can reveal immune system abnormalities. In rare cases, an overly aggressive immune response indicated by a high titer could suggest an underlying autoimmune disease, where the body's immune system attacks its own cells as if they were foreign substances.
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Understanding Your Results
Autoimmune disease diagnosis often requires multiple tests and careful interpretation by healthcare professionals. Abnormal results may indicate immune system dysfunction, but additional specific autoantibody tests and clinical evaluation are typically needed for definitive diagnosis and treatment planning.
Important Considerations
The information here is for educational purposes only and is not a substitute for professional medical advice. Always consult with a healthcare provider for diagnosis and treatment.
