Guest guest Posted April 8, 2004 Report Share Posted April 8, 2004 WebMD Today HomeWebMD News Center Member Services Newsletters & AlertsBoards & EventsWebMD UniversityMy WebMDFind a Physician Medical Info Diseases & ConditionsCheck SymptomsMedical LibraryDrugs & HerbsQuizzes, CalculatorsClinical TrialsHealth Plan Health & Wellness Women, Men, LifestylePregnancy & FamilyDiet & Nutrition Who We Are About WebMDPrivacy & YouSite Map You are in Diseases & Conditions. Choose a TopicAll ConditionsADD/ADHDAllergiesAlzheimer'sArthritisAsthmaBack PainBreast CancerCancerDentalDepressionDiabetesEye HealthHeart DiseaseHepatitisHIV/AIDSHypertensionMen's ConditionsMental HealthMigraines/HeadachesMultiple SclerosisOsteoporosisParkinson'sSexual ConditionsSkin & BeautyStrokeWeight ControlWomen's Conditions Health Topics | Symptoms | Medical Tests | Medications | Wellness | Support Organizations Test Overview Why It Is Done How To Prepare How It Is Done How It Feels Risks Test Results What Affects the Test What To Think About Credits Antinuclear Antibodies (ANA) Test Overview The body's immune system attacks and destroys foreign substances such as bacteria and viruses. However, in disorders known as autoimmune diseases, the immune system attacks and destroys the body's normal tissues. When a person has an autoimmune disease, the immune system produces antibodies that attach to the body's own cells as if they were foreign substances, often causing them to be damaged or destroyed. Antinuclear antibodies (ANA) are a type of abnormal antibody that can indicate the presence of an autoimmune disease (such as systemic lupus erythematosus or rheumatoid arthritis). However, an ANA test alone cannot diagnose a specific disease. A thorough medical history, physical examination, and other tests are needed confirm a suspected autoimmune disease. This test is done on a blood sample taken from a vein.Why It Is Done A test for antinuclear antibodies (ANA) is done to help diagnose: Systemic lupus erythematosus (SLE). Other suspected autoimmune diseases. How To Prepare No special preparation is required before having this test.How It Is Done The person drawing blood will wrap an elastic band around your upper arm to temporarily stop the flow of blood through the veins of your arm. This makes it easier to put the needle into a vein properly because the veins below the band get larger and do not collapse easily. The needle site is cleaned with alcohol and the needle is inserted. More than one needle stick may be needed if the needle does not get placed correctly or if the vein cannot supply enough blood. When the needle is properly placed in the vein, a collection tube will be attached to the needle. Blood will flow into the collection tube. Sometimes more than one tube of blood is collected. When enough blood has been collected, the band around your arm will be removed. A gauze pad or cotton ball is placed over the puncture site as the needle is withdrawn. Pressure is applied to the puncture site for several minutes and then a small bandage is often placed over it.How It Feels You may feel nothing at all from the needle puncture, or you may feel a brief sting or pinch as the needle goes through the skin. Some people feel a stinging pain while the needle is in the vein. However, many people do not feel any pain (or have only minor discomfort) once the needle is positioned in the vein. The amount of pain you feel depends on the skill of the person drawing the blood, the condition of your veins, and your sensitivity to pain.Risks There is very little risk of complications from having blood drawn from a vein. You may develop a small bruise at the puncture site. You can reduce the risk of bruising by keeping pressure on the site for several minutes after the needle is withdrawn. Rarely, the vein may become inflamed after the blood sample is taken. This condition is called phlebitis and is usually treated with a warm compress applied several times daily. Continued bleeding can be a problem for people with bleeding disorders. Aspirin, warfarin (Coumadin), and other blood-thinning medications can also make bleeding more likely. If you have bleeding or clotting problems, or if you take blood-thinning medication, tell the person before your blood is drawn.Test Results The results of an antinuclear antibody (ANA) test are expressed in titers. A titer is a measure of how much the blood sample can be diluted before the presence of the antibodies can no longer be detected. A titer of 1 to 80 (1:80) means that antibodies could be last detected when 1 part of the blood sample was diluted by 80 parts of another liquid (usually a dilute salt solution). A larger second number indicates that the antibodies are present in greater concentration. Therefore, a titer of 1 to 320 indicates a higher concentration of antibodies in the blood than a titer of 1 to 80. Normal Normal values may vary from lab to lab. Antinuclear antibodies Titer below 1:20 or 1:40, depending on the test method used Greater than normal values may mean A high ANA titer may mean that the person tested has systemic lupus erythematosus (lupus can be present with titers from 1 to 40 and higher). Almost all people with systemic lupus erythematosus (SLE) have a high ANA titer. However, most people with a high ANA titer do not have SLE. Only about one-third of people who are referred to a rheumatologist for high ANA titers are diagnosed with lupus. Other conditions may cause a high ANA titer. About 30% to 40% of people with rheumatoid arthritis have a high ANA titer. Many conditions may result in a high ANA titer. These conditions include autoimmune diseases (such as scleroderma, Sjögren's syndrome, juvenile rheumatoid arthritis, and myositis), Raynaud's syndrome, viral infections, and liver disease. Although an ANA titer may help support a diagnosis for these conditions, it is not used by itself to confirm a diagnosis. A thorough medical history, physical examination, and other tests are needed confirm a suspected autoimmune disease. Some apparently healthy individuals have high levels of antinuclear antibodies. For instance, some people with a family history of autoimmune disease may have a high ANA titer. The higher the titer, however, the more likely it is that the person has SLE. What Affects the Test The medications hydralazine (Apresoline), procainamide (Procan, Pronestyl, Promine), and certain anticonvulsants (such as Dilantin) can cause a form of systemic lupus erythematosus (SLE) called drug-induced lupus. Lupus resulting from these medications may cause a high antinuclear antibody (ANA) titer. Certain medications can cause an abnormally high ANA titer. These medications include some antibiotics (including isoniazid, penicillin, and tetracycline), birth control pills, and some diuretics. Aging can affect the levels of antinuclear antibodies, and some older adults (5% to 40%) may have mildly elevated levels. Rough handling, contamination, or inadequate refrigeration of the blood sample can cause inaccurate test results. What To Think About The result of an antinuclear antibody (ANA) test is used along with a thorough medical history, physical examination, or other tests to diagnose systemic lupus erythematosus (SLE) or other autoimmune diseases. SLE cannot be diagnosed by the results of the ANA test alone. Some healthy people can have an elevated ANA titer. Also, ANA levels can increase with age. A method to detect antinuclear antibodies called enzyme-linked immunosorbent assay (ELISA) is replacing the previous method of testing (immunofluorescent assay technique, or IFA). The ELISA method is less likely to produce a false-positive ANA result than the IFA method. Credits Author Renée Spengler, RN, BSN Associate Editor Greer Primary Medical Reviewer Adam Husney, MD- Family Practice Specialist Medical Reviewer Stanford M. Shoor, MD- Rheumatology Last Updated 6/26/2002 ^back to top To Search the Help Last updated: June 26, 2002 Print-Friendly Version © 1995-2004, Healthwise, Incorporated, P.O. Box 1989, Boise, ID 83701. All Rights Reserved.This information is not intended to replace the advice of a doctor. Medscape for Physicians | Medscape for Healthcare Professionals Corporate | Contact Us Terms and Conditions | Privacy Policy and Agreement ©1996-2004 WebMD Inc. All rights reserved. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You are posting as a guest. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.