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Antinuclear antibody

Antinuclear antibody (ANA) test — a core screening tool for systemic autoimmune diseases.

Blood test that searches for antibodies the body produces against its own cell nuclei. It is used in the screening of lupus and other autoimmune diseases.

Indication

  • Unexplained joint pain, morning stiffness or joint swelling
  • Butterfly-shaped rash on the face or marked sensitivity to sunlight
  • Unexplained fever, fatigue or weight loss
  • Suspicion of systemic lupus erythematosus (SLE)
  • Evaluation of connective tissue diseases such as Sjögren's syndrome, scleroderma or myositis
  • Autoimmune workup in cases of recurrent miscarriage
  • Differential diagnosis of autoimmune hepatitis in liver function abnormalities

Preparation

  • No special preparation is required
  • Fasting is not mandatory; water can be consumed
  • Medications in use (especially those that may cause drug-induced ANA positivity such as hydralazine, procainamide or isoniazid) should be reported to the physician
  • Recent infections should be communicated to the laboratory
  • Low-titer positivity may also be seen in older or otherwise healthy individuals

How it's performed

  1. Approximately 3-5 mL of venous blood is drawn into a gel tube
  2. Serum is separated
  3. Indirect immunofluorescence (IFA) is used as the reference method
  4. Serum is applied to HEp-2 cell culture and examined under a fluorescence microscope
  5. When positive, titer (such as 1:80, 1:160, 1:320) and fluorescence pattern (homogeneous, speckled, centromeric, nucleolar, etc.) are reported
  6. When needed, specific subtype antibodies such as anti-dsDNA, anti-Sm, anti-SSA/SSB are also tested

Post-procedure

  • Results are usually available within 1-3 working days
  • A positive result alone does not establish a diagnosis; it must always be interpreted with clinical findings
  • Additional tests (anti-dsDNA, complement, anti-CCP, ENA panel) may be requested for diagnosis
  • Evaluation by a rheumatologist is recommended
  • In low-titer positivity, a follow-up test in 3-6 months may be planned

Risks

  • Temporary bruising or pain at the blood draw site
  • Low-titer false positivity in healthy individuals
  • Transient positivity related to certain medications or infections
  • Very rare vasovagal reaction

FAQ

Does a positive ANA mean I have lupus?

No. ANA positivity is a screening result; it cannot diagnose lupus on its own. It must be interpreted together with clinical findings and additional antibody tests.

Can ANA be positive in healthy people?

Yes. Especially with increasing age and at low titers (such as 1:80), ANA positivity can be seen in healthy individuals and does not necessarily indicate disease.

Do I need to fast before the test?

No. Fasting is not required and you can continue your usual diet.

How long does it take to get the result?

Depending on the method and the laboratory, results are usually ready within 1-3 working days.