An Antinuclear Antibody (ANA) Screen is a blood test used for autoimmunity screening. It looks for a group of immune proteins called antinuclear antibodies—antibodies that mistakenly target parts of your own cells, especially the cell nucleus (where DNA is stored). A positive ANA does not diagnose a specific disease by itself, but it can be an important clue that your immune system may be reacting in a way that’s seen in certain systemic autoimmune diseases.

Results are typically reported as negative or positive. Some labs also report how strong the result is (often called a titer) and may note a pattern of staining if the method is immunofluorescence. In general:

Negative ANA means antinuclear antibodies were not detected (or were below the lab’s cutoff). This makes some autoimmune conditions—especially systemic lupus erythematosus (SLE)—less likely, though it does not completely rule them out in every situation.

Positive ANA means antinuclear antibodies were detected. This can be seen in autoimmune diseases such as lupus or Sjögren’s syndrome, but it can also occur in people without an autoimmune disease (especially at low levels), in some infections, with certain medications, or sometimes with aging. Because of this, a positive ANA is best interpreted along with your symptoms, physical exam, and follow-up antibody tests (such as anti-dsDNA, ENA panel, or others) if clinically indicated.

Clinicians most often order an ANA Screen as a first-line test when symptoms suggest a systemic autoimmune (connective tissue) disorder. It is commonly used for lupus screening and to evaluate unexplained inflammation affecting multiple body systems.

Your doctor may recommend an ANA test if you have symptoms such as:

• Ongoing joint pain, swelling, or stiffness (especially with other systemic symptoms)
• Unexplained fatigue that persists for weeks to months
• Skin rashes (including a photosensitive rash that worsens with sun exposure) or mouth/nose ulcers
• Raynaud’s phenomenon (fingers/toes turning white/blue in cold or stress)
• Dry eyes or dry mouth (possible Sjögren’s syndrome)
• Unexplained fevers, swollen glands, or weight changes
• Chest pain with deep breaths or shortness of breath (possible pleuritis/pericarditis)
• Kidney-related findings (protein or blood in urine, swelling in legs/face)
• Neurologic symptoms (numbness/tingling, headaches, seizures) when autoimmune disease is suspected

It may also be ordered if you have abnormal results on other tests that raise concern for inflammation or autoimmune disease, such as elevated ESR/CRP, low blood counts, or abnormal urinalysis. In most cases, ANA testing is most useful when there is a strong clinical reason to suspect autoimmune disease—testing without symptoms can lead to confusing results because some healthy people can have a positive ANA.

• Systemic lupus erythematosus (SLE)
• Sjögren’s syndrome
• Systemic sclerosis (scleroderma)
• Mixed connective tissue disease (MCTD)
• Polymyositis and dermatomyositis
• Autoimmune hepatitis (ANA may be supportive alongside liver-specific testing)
• Drug-induced lupus (associated with certain medications)
• Rheumatoid arthritis (ANA can be positive in some people, though other tests are often more specific)
• Autoimmune thyroid disease (e.g., Hashimoto’s thyroiditis; ANA can sometimes be present)

• Early detection support for systemic autoimmune disease when symptoms suggest lupus or other connective tissue disorders
• Clarifying the cause of chronic symptoms such as fatigue, joint pain, rashes, fevers, or dry eyes/mouth
• Guiding next-step testing (e.g., ENA panel, anti-dsDNA, complement levels) to narrow down the type of autoimmunity
• Monitoring and care planning in people with known autoimmune disease when paired with symptom tracking and other labs (ANA itself may not closely track disease activity for all conditions)
• Reducing diagnostic uncertainty by helping distinguish autoimmune inflammation from other causes when used with clinical evaluation