What is Anti-nuclear AB titer?

Anti-nuclear antibody (ANA) titer is a blood test that measures the level of antibodies in your blood that are directed against your own cell nuclei.

ANA titers are used to help diagnose and monitor autoimmune diseases such as lupus, rheumatoid arthritis, and Sjogren's syndrome.

A positive ANA titer means that you have antibodies in your blood that are reacting against your own cell nuclei, but it does not necessarily mean that you have an autoimmune disease. Other tests and clinical findings are necessary to make a definitive diagnosis.

Reasons for the test

ANA titer tests are typically ordered when you have symptoms or signs suggestive of an autoimmune disease, such as:

- Joint pain or swelling

- Muscle pain or weakness

- Fatigue

- Skin rash

- Dry eyes or mouth

- Sensitivity to sunlight

- Unexplained weight loss

- Fever

The ANA titer test may also be ordered if you have a family history of autoimmune disease, or if you are taking certain medications that can cause drug-induced lupus.

How to prepare for the test

No special preparation is required for an ANA titer test. However, you should inform your doctor if you are taking any medications, as some medications can interfere with the test results.

What to expect during the test

An ANA titer test is a blood test. A small amount of blood will be drawn from a vein in your arm and sent to a laboratory for analysis. The blood draw typically takes just a few minutes.

Understanding your results

ANA titer results are reported in titers, which are dilutions of your blood serum.

- A titer of 1:40 or less is considered negative and suggests that you do not have an autoimmune disease.

- A titer of 1:80 or higher is considered positive and suggests that you may have an autoimmune disease.

It is important to note that a positive ANA titer does not necessarily mean that you have an autoimmune disease. Other tests and clinical findings are necessary to make a definitive diagnosis.

If your ANA titer is positive, your doctor may order additional tests to determine the specific autoimmune disease that you may have. These tests may include:

- Anti-double-stranded DNA (anti-dsDNA) antibody test

- Anti-Smith (anti-Sm) antibody test

- Anti-Ro/SSA and anti-La/SSB antibody tests

- Rheumatoid factor test

- Erythrocyte sedimentation rate (ESR)

- C-reactive protein (CRP) test

Based on the results of these tests and your symptoms, your doctor can diagnose and treat any underlying autoimmune disease.