Arthritis Diagnosis Print Understanding the ANA Blood Test (Antinuclear Antibody Test) Medically reviewed by linkedin Medically reviewed by Anita C. Chandrasekaran, MD, MPH on November 06, 2019 Anita Chandrasekaran, MD, MPH is board-certified in Internal Medicine and currently works as a clinical fellow at Yale University. Learn about our Medical Review Board Anita C. Chandrasekaran, MD, MPH Written by facebook Written by Carol Eustice Carol Eustice is a writer who covers arthritis and chronic illness. She is the author of "The Everything Health Guide to Arthritis." Learn about our editorial policy Carol Eustice Updated on December 05, 2019 Dana Neely / The Image Bank / Getty Images More in Arthritis Diagnosis Causes & Risk Factors Living With Support & Coping Joint Pain Rheumatoid Arthritis Gout Ankylosing Spondylitis Symptoms Treatment Osteoarthritis More Arthritis Types & Related Conditions Psoriatic Arthritis View All In This Article Table of Contents Expand How It's Performed Report ANA Titer Pattern Significance What Results Mean In Various Diseases View All Back To Top In order to understand the ANA blood test (antinuclear antibody test), it is important to first understand different types of antibodies. Antibodies are proteins produced by white blood cells, which normally circulate in the blood to defend against foreign invaders, such as bacteria, viruses, and toxins.Autoantibodies, instead of acting against foreign invaders, attack the body's own cells. This is abnormal.Antinuclear antibodies are a unique group of autoantibodies which have the ability to attack structures in the nucleus of cells. The nucleus of a cell contains genetic material, known as DNA (deoxyribonucleic acid). An ANA blood test (antinuclear antibody test) is usually performed on a blood sample as part of the diagnostic process for certain autoimmune diseases. How the Test Is Performed To perform the ANA blood test, sometimes called FANA (fluorescent antinuclear antibody test), a blood sample is drawn from the patient and sent to the lab for testing. Serum from the blood specimen is added to microscope slides which have commercially prepared cells on the slide surface. If the patient's serum contains antinuclear antibodies, they bind to the cells (specifically the nuclei of the cells) on the slide. Make Blood Draws Easier A second antibody, commercially tagged with a fluorescent dye, is added to the mix of patient's serum and commercially prepared cells on the slide. The second (fluorescent) antibody attaches to the serum antibodies and cells which have bound together. When the slide is viewed under an ultraviolet microscope, antinuclear antibodies appear as fluorescent cells. If fluorescent cells are observed, the ANA blood test result is positive.If fluorescent cells are not observed, the ANA blood test result is negative. ANA Blood Test Report An ANA blood test report has three parts: Positive or negative for ANAIf positive, a titer is determined and reportedThe pattern of fluorescence is reported ANA Titer A titer is determined by repeating the positive test with serial dilutions until the test yields a negative result. The last dilution which yields a positive result (i.e., fluorescence observed under the microscope) is the titer that is reported. Here is an example: Serial Dilutions:1:10 positive1:20 positive1:40 positive1:80 positive1:160 positive (titer reported as 1:160)1:320 negative The Significance of ANA Pattern ANA titers and patterns can vary between laboratory testing sites due to variation in the methodology used. The commonly recognized patterns include: Homogeneous - total nuclear fluorescence due to an antibody directed against DNA or histone proteins. Common in systemic lupus erythematosus.Peripheral - fluorescence occurs at edges of the nucleus in a shaggy appearance. Anti-DNA and anti-nuclear envelope antibodies cause this pattern. Also seen in systemic lupus erythematosus.Speckled - speckled fluorescense due to an antibody directed against different nuclear antigens.Nucleolar - from antibodies directed against specific proteins involved in the maturation of RNA. Seen in people with scleroderma (systemic sclerosis). What Does a Positive ANA Blood Test Result Mean? Antinuclear antibodies are found in people with various autoimmune diseases, but not exclusively. Antinuclear antibodies can also be found in people with infections, cancer, lung diseases, gastrointestinal diseases, hormonal diseases, blood diseases, skin diseases, in elderly people, or people with a family history of rheumatic disease. The prevalence of antinuclear antibodies in healthy people is estimated to be 3-15%, but is strongly age-dependent, and increases to 10-37% in healthy people over age 65. ANA results are just one factor considered when a diagnosis is being formulated. A patient's clinical symptoms and other diagnostic tests must also be considered by the doctor. The medical history is also significant because some prescription drugs can cause "drug-induced antinuclear antibodies." Incidence of ANA in Various Diseases Statistically-speaking, the incidence of positive ANA test results (in percent per condition) is: Systemic lupus erythematosus (lupus or SLE) - over 95 percentProgressive systemic sclerosis (scleroderma) - 60 to 90 percentRheumatoid arthritis - 25 to 30 percentSjogren's syndrome - up to 80 percentFelty's syndrome - over 75 percentJuvenile arthritis - 15 to 30 percent Subsets of the ANA blood tests are sometimes used to determine the specific autoimmune disease. For this purpose, a doctor may order anti-dsDNA, anti-Sm, Sjogren's syndrome antigens (SSA, SSB), Scl-70 antibodies, anti-centromere, anti-histone, and anti-RNP. How Is Lupus Diagnosed? A Word From Verywell The ANA blood test is complicated. That said, the results—positive or negative, titer, pattern, and subset test results—can provide doctors with valuable clues to help diagnose autoimmune rheumatic diseases. Was this page helpful? Thanks for your feedback! Dealing with chronic inflammation? An anti-inflammatory diet can help. Our free recipe guide shows you the best foods to fight inflammation. Get yours today! Sign Up You're in! Thank you, {{form.email}}, for signing up. There was an error. Please try again. What are your concerns? Other Inaccurate Hard to Understand Submit Article Sources Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial policy to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy. Nosal RS, Varacallo M. Biochemistry, antinuclear antibodies (ANA) [Updated 2018 Dec 20]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2019 Jan. American Association for Clinical Chemistry. Antinuclear antibody (ANA). Updated November 19, 2019. American College of Rheumatology. Antinuclear antibodies (ANA). Updated March, 2019. Additional Reading Davidsohn I, Sanford AH, Todd JC. Clinical Diagnosis by Laboratory Methods. Sagwan Press; 2015. Continue Reading