What is the antinuclear antibody (ANA) test and what does a positive result mean?

The antinuclear antibody (ANA) test is a blood test used to help diagnose autoimmune disorders by detecting antibodies that mistakenly attack the body's healthy cells and tissues. Normally, the immune system produces antibodies to fight foreign invaders like viruses and bacteria; however, in the case of antinuclear antibodies, they target the cell nucleus, which controls vital cellular functions and sends signals necessary for cell activity [2]. It is normal to have very small amounts of these antibodies in the blood, but significantly elevated levels may indicate the potential presence of an autoimmune disorder such as systemic lupus erythematosus, which is the most common form of lupus [2].

A positive ANA test does not in itself constitute a definitive diagnosis of a specific disease, as the result is evaluated alongside clinical symptoms and other medical examinations to reach an accurate diagnosis [2].

When does a doctor order an ANA test?

A healthcare provider may recommend this test if the patient is experiencing symptoms that might indicate an autoimmune disorder. These symptoms depend primarily on the part of the body affected, but they may include a range of common warning signs. These include unexplained fever, skin rashes, blisters, or noticeable changes in skin color, in addition to persistent feelings of fatigue and exhaustion [2].

This may also be accompanied by joint pain with stiffness and swelling, muscle pain, swollen glands, and abdominal pain [2]. There are no significant risks associated with this test; it only requires drawing a blood sample from a vein, a procedure that typically takes less than five minutes. However, you must inform your doctor of all medications you are taking, as some drugs may affect the accuracy of the test results [2].

What does a positive antinuclear antibody test result mean?

A positive result means that antinuclear antibodies have been detected in the bloodstream. However, a positive ANA test does not always confirm the presence of lupus or any other immune disease [2]. In fact, some healthy individuals have antinuclear antibodies in their blood naturally; levels tend to rise with age and are particularly common in many women over the age of 65 [2].

In addition to the possibility of indicating systemic lupus erythematosus, a positive result may be associated with the following conditions:

• Other types of autoimmune diseases such as rheumatoid arthritis, scleroderma, and Sjögren's syndrome [2].
• Viral infections, where antibodies resulting from a virus are typically present in the blood for a short time [2].
• Other health conditions that can cause the appearance of these antibodies, such as certain types of cancer [2].
• Side effects of certain medications that can induce the appearance of these antibodies in the blood [2].

Next medical steps after a positive result

Since there is no single specific test for diagnosing lupus, and symptoms often overlap with other diseases, a positive ANA test requires further evaluations that may take some time to reach a precise diagnosis [1]. If your test result is positive, your doctor or a rheumatologist—a doctor specializing in the treatment of joints, muscles, connective tissues, and immune diseases—will order a set of additional tests [3].

These additional procedures include asking the patient about their detailed personal and family medical history and performing a complete physical examination [1]. The doctor may also request additional blood tests, such as other antibody tests, a complete blood count (CBC), complement tests, as well as urine tests, or, in some cases, skin or kidney biopsies to examine tissue under a microscope [1].

For a deeper understanding of the nature of this disease and its various effects on different body systems, you can review our detailed article on Lupus: A Multisystem Autoimmune Disease and Challenges in Diagnosis and Treatment (Arabic). Regular follow-up with a specialized medical team is the most important step for addressing any abnormal results and managing the condition effectively [3].

Medical references

• Lupus
• ANA (Antinuclear Antibody) Test
• Lupus Basics