This may result in RF levels decreasing. 3.Calibrator: Human serum or defibrinated plasma. 2004-2023 Healthline Media UK Ltd, Brighton, UK, a Red Ventures Company. RF and IgG join to form immune complexes that contribute to the disease process. If you felt faint, you may need a little recovery time, but you'll be able to go home as soon as you're feeling better. The RF test isn't used as a screening tool because the majority of healthy people who have elevated RF don't go on to develop RA. RF have been associated with three major immunoglobulin classes: IgM, IgG, and IgA. A positive for rheumatoid factor test results means that it can lead to or is the cause of inflammatory symptoms from an autoimmune disorder. Rheumatoid Factor is a topic covered in the Davis's Lab & Diagnostic Tests. This is more likely if your levels are high and substantially more likely when both tests are positive, in which case, your healthcare provider may run these tests again at a later time. Get our printable guide for your next doctor's appointment to help you ask the right questions. While high RF levels may indicate rheumatoid arthritis, in many instances, this condition is not the only reason that a person might have high RF levels. %%EOF Obesity linked to 21 genes related to Alzheimers disease, study finds, Blood tests for rheumatoid arthritis: Types and what to know. You wont have to do anything to prepare. Reporting results Positive reaction: agglutination of the latex suspension indicates the presence of rheumatoid factor in the specimen. Rheumatoid factor (RF) is the traditional designation for autoantibodies directed at the Fc chains of IgG molecules. QUALITY CONTROL RF Positive and Negative Control should be included . If you have questions, talk to your doctor before the test. The most commonly used serological method is based on latex agglutination test. A rheumatoid factor test measures the amount of rheumatoid factor in your blood. Bethesda (MD): U.S. Department of Health and Human Services; Rheumatoid Arthritis; [updated 2019 Sep; cited 2022 Jun 3]; [about 6 screens]. A standard blood draw is a low-risk procedure that's perfectly safe for most people. Many doctors and researchers feel that a positive rheumatoid factor test result may predict a more severe pattern of symptoms and overall disease course. Rheumatoid factor (RF) is the autoantibody that was first found in rheumatoid arthritis.It is defined as an antibody against the Fc portion of IgG and different RFs can recognize different parts of the IgG-Fc. Higher levels of RF can also occur in other conditions. You may experience some pain, swelling, and/or bruising around where your blood was drawn, but this should go away within a few days. American Association for Clinical Chemistry (AACC): Lab Tests Online. Rheumatic factor (RF) might be attach to others antibodies because RF . They usually affect the same joints on both sides of the body and tend to come and go. Rheumatoid arthritis (RA) is a systemic, autoimmune, chronic inflammatory disease that affects bone metabolism by increasing bone resorption, leading to osteoporosis and a high risk of fracture [1,2].The presence of numerous proinflammatory cytokines in RA is associated with the activation of osteoclastogenesis, with tumor necrosis factor alpha (TNF-) playing a leading role in this process. Reagent used is a suspension of polystyrene latex particles in glycine-saline buffer with pH: 8.6 0.1, coated with human gamma globulin. The data presented show a good correlation between this new method and the older quantitative latex tube rheumatoid factor test. Rheumatoid factor can also cause other symptoms seen in autoimmune disorders like Sjogrens Syndrome. This test measures the level of a substance called rheumatoid factor (RF) in your blood. You'll mail your sample to a lab for testing. This may depend on a variety of factors. [Updated 2021 Jul 28; cited 2022 Jun 7]. High levels of rheumatoid factor in the blood are most often associated with autoimmune diseases, such as rheumatoid arthritis and Sjogren's syndrome. What Is Seronegative Rheumatoid Arthritis (RA)? In certain cases, however, patients may test positive for rheumatoid factor, yet remain healthy and never experience any obvious symptoms. Place 0.05 ml of the serum into one circle of slide. antigen. CCP antibodies. It isnt completely known what triggers the autoimmune response that causes rheumatoid arthritis. Philadelphia, Pa.: Saunders Elsevier; 2013. http://www.clinicalkey.com. Between 5% and 10% of healthy people (or even more according to some studies), particularly older individuals, have a low to moderate amount of RF in their blood for unknown reasons. Rheumatoid factor. One needs to remember that even in the blood of healthy people sometimes the rheumatoid factor test is positive. RF is an autoantibody, which is a type of protein that the immune system produces. The presence of RF is not essential for the diagnosis of RA (so-called . Procedure: Bring the reagents and sample at room temperature. Rinvoq (upadacitinib) is a prescription drug used to treat certain types of arthritis and other conditions. Sheep RBCs coated with rabbit IgG will be positive in 60% to 70% (and have fewer false-positives). Firestein GS, et al. A rheumatoid factor test is one of a group of blood tests primarily used to help pinpoint a diagnosis of rheumatoid arthritis. If you feel faint or nauseated, let your doctor know. Anti-cyclic citrullinated peptide (anti-CCP) antibodies, Erythrocyte sedimentation rate (ESR, or sed rate), Inflammatory lung diseases, such as sarcoidosis. 0000006077 00000 n 2005 - 2023 WebMD LLC. 0000002459 00000 n RF is not detected in all patients diagnosed with RA. Rheumatoid arthritis test commonly abbreviated RA is a Quantitative immunological estimation of Rheumatoid Arthritis (RA) factor in human serum by latex agglutination method. This usually takes less than five minutes. Many rheumatic conditions and other chronic inflammatory processes also may produce rheumatoid factors. antibody. High levels of rheumatoid factor in the blood are most often associated with autoimmune diseases, such as rheumatoid arthritis and Sjogren's syndrome. A single copy of these materials may be reprinted for noncommercial personal use only. Both qualitative and. 0000001871 00000 n All rights reserved. xref However, seronegative arthritis is still a serious condition that can require medical management and treatment. Available from: National Institute of Arthritis and Musculoskeletal and Skin Diseases [Internet]. They'll find a vein (usually on the inside of your elbow), tie an elastic band around your arm above the vein, and swab the area with alcohol to clean it. This content does not have an English version. Many people with rheumatoid arthritis or Sjgren syndrome have positive RF tests. A reference sample with a known concentration is then used to compare the value obtained. If you have symptoms of rheumatoid arthritis, but your RF test results are normal, your provider may order more tests to make a diagnosis. This article discusses RF testing, normal RF ranges, and what abnormal levels mean. The sensitivity of the rheumatoid factor blood test is 85 percent, which means that 85 percent of the general population can be expected to test negative, but 15 percent might test positive even without having RA. Carol Eustice is a writer covering arthritis and chronic illness, who herself has been diagnosed with both rheumatoid arthritis and osteoarthritis. Rheumatoid factors are antibodies directed against the Fc fragment of IgG. endstream endobj 443 0 obj<>/Outlines 18 0 R/Metadata 70 0 R/PieceInfo<>>>/Pages 69 0 R/PageLayout/OneColumn/OCProperties<>/StructTreeRoot 72 0 R/Type/Catalog/LastModified(D:20090304142253)/PageLabels 67 0 R>> endobj 444 0 obj<>/PageElement<>>>/Name(HeaderFooter)/Type/OCG>> endobj 445 0 obj<>/Font<>/ProcSet[/PDF/Text]/Properties<>/ExtGState<>>>/Type/Page>> endobj 446 0 obj<> endobj 447 0 obj[/ICCBased 456 0 R] endobj 448 0 obj<> endobj 449 0 obj<> endobj 450 0 obj<>stream The test is performed using a reagent kit. A rheumatoid factor (RF) test is a blood test that's often used to help diagnose rheumatoid arthritis (RA). Because rheumatoid factor may be present in other conditions, and in some healthy people, the test for it should be combined with other tools and criteria for it to be useful in diagnosis. The titre is reported as the reciprocal of the highest dilution, which shows a positive test result. They will also examine you and may order other types of lab tests, such as X-rays, an MRI, an ultrasound, or other scans. All rights reserved. Rheumatoid Factor. Rheumatoid factor (RF) is an immune system protein that attacks healthy cells in the body. University of California San Francisco: Benioff Children's Hospital. 442 0 obj <> endobj It's possible that you may develop RA over time. Rheumatoid Factor test 78,471 views May 19, 2018 Video demonstration of Rheumatoid factor test. Accessed May 5, 2016. Place 0.05 ml of the serum into one circle of slide. These other tests may include: The amount of rheumatoid factor in your blood may also help your doctor choose the treatment approach that will work best for your situation. Since RF is present in up to 80% of adults who have RA, this may be one of the first tests your healthcare provider orders if you have signs and symptoms of RA, such as: The RF test can also help distinguish RA from other types of arthritis like osteoarthritis or psoriatic arthritis and may rule out other conditions with similar symptoms. A healthy immune system is vital to the functioning of the human body. Johns Hopkins Medicine; Health Library: Rheumatoid Arthritis; [cited 2022 Jun 3]; [about 5 screens]. RASN is dedicated to providing the most up to date and trusted information. Here's a look at more specific test results regarding rheumatoid arthritis: If you have symptoms of RA, and your RF and/or anti-CCP results are high, the likely result is a diagnosis of seropositive rheumatoid arthritis. Some of the main blood tests used include: erythrocyte sedimentation rate (ESR) - which can help assess levels of inflammation in the body. Before the test, you may need to fill out some forms for insurance or consent for the procedure. American Association for Clinical Chemistry (AACC): Lab Tests Online. Roth, L. (2022). Anyone who suspects they have rheumatoid arthritis or another autoimmune condition should contact a doctor. Quantitative testing should be done to confirm diagnosis of RA. . The RA factor normal range is below 6.0 IU/ml, But many labs use different type of kits Hence their normal value may change . An RF test is not used to diagnose osteoarthritis. Rheumatoid factors are proteins made by the immune system. Our website is not intended to be a substitute for professional medical advice, diagnosis, or treatment. You may feel a little sting when the needle goes in or out. A variety of conditions have been shown to occur from these autoimmune responses. This should go away very quickly, so let the technician know if it's extremely painful or bothersome and/or if you begin to feel lightheaded or dizzy. The onset of rheumatoid arthritis and other autoimmune conditions, cancers, and bacterial infections can all affect RF levels. Learn more about seronegative rheumatoid arthritis here. The blood is drawn then analyzed for the presence of this particular protein. Seattle (WA): OneCare Media; c2022. rheumatoid factor. If a doctor suspects rheumatoid arthritis, they often order other blood tests alongside or after an RF test. Typically, these symptoms cause inflammation in the synovium a layer of soft tissue on the inner surface of joints, eventually leading to rheumatoid arthritis. Other diagnostic criteria for seropositive RA include: In general, the higher your RF level, the more severe your disease is likely to be, but this is not a rule. Keep in mind that this test is never used by itself to definitively diagnose someone with rheumatoid arthritis, Sjgren's syndrome, or any other autoimmune disease. Tilt the slide back and forth for 2 minutes in a rotary shaker so that the mixture rotates slowly. what substance is being tested for in the patient's serum when performing the RFR test? It could take a few days for your rheumatoid factor test results to come back. But even if the test results show you have a high level of it, your doctor will want to do other tests before they make a diagnosis. In addition, the nephelometric and latex tube testing of sera from normal, rheumatoid and non-rheumatoid patients yielded similar results, suggesting the two procedures share a similar immunologic specificity. The presence of rheumatoid factor, especially in low titer, is far from diagnostic for rheumatoid arthritis. Turnaround time is defined as the usual number of days from the date of pickup of a specimen for The Rheumatoid Factor (RA) quantitative test helps to detect the levels of rheumatoid factor in the blood and to diagnose the presence of an autoimmune disease such as Rheumatoid Arthritis. If you have signs and symptoms of RA and you had a negative RF test but no other tests at the same time, the next likely step is an anti-CCP test. A normal immune response to infection often involves the production of proteins such as antibodies to kill these invading organisms. Most recommended products are used daily by our team and paid for with our personal money. Rheumatoid factor can be detected in synovial fluid, pleural fluid, and pericardial fluid, but contributes little more than a positive serum test. Rheumatoid factor is an antibody that is detectable in the blood of approximately 80% of adults with rheumatoid arthritis. <]>> Place similar quantities of positive and negative controls in separate circles. RF testing is mostly used with other tests to help diagnose rheumatoid arthritis. There is very little risk to having a blood test. Other autoimmune diseases that can raise rheumatoid-factor levels include: A number of infections or other medical conditions can be associated with positive rheumatoid factor test results, too. https://labtestsonline.org/understanding/analytes/rheumatoid/tab/test. What is seronegative rheumatoid arthritis? Patients who test negative for rheumatoid factor but still exhibit symptoms and meet other diagnostic criteria may still be diagnosed with rheumatoid arthritis. These are the autoantibodies produced . Rheumatoid factor is an autoantibody that is formed in people who have rheumatoid arthritis. Ordering information These slide agglutination assay tests are used for the qualitative and semi-quantitative determination of rheumatoid factor in human serum. It is not exactly known what causes rheumatoid factor to develop in the blood. As RF is an IgM class of antibody directed against the Fc portion of the IgG molecule, it is detected by its ability to agglutinate the latex particles coated with IgG molecule. But rheumatoid factor may be detected in some healthy people, and people with autoimmune diseases sometimes have normal levels of rheumatoid factor. Available from: Mayo Clinic [Internet]. 442 17 Rheumatoid arthritis. 1.Microplate: wells coated with Purified Rheumatoid Factor IgG antigen. endstream endobj 457 0 obj<>/Size 442/Type/XRef>>stream You can learn more about how we ensure our content is accurate and current by reading our. If you have health insurance, this test should be covered as any diagnostic test would be, though you may need to pay a co-pay and/or co-insurance. If your RF test and/or anti-CCP test came back positive but you don't have RA symptoms, you're not necessarily in the clear. Rheumatoid Arthritis Support Network. In: StatPearls [Internet]. We link primary sources including studies, scientific references, and statistics within each article and also list them in the resources section at the bottom of our articles. If a patient tests positive for rheumatoid factor it helps to reach a diagnosis, but its presence doesn't confirm it. 8. 458 0 obj<>stream Rheumatoid factor was first described in connection to rheumatoid arthritis in 1940. Your healthcare provider will tell you where to go. Rochester (NY): University of Rochester Medical Center; c2022. Your RF test results may come back as either a value or a titer, which indicates the concentration of RF in your blood. The blood is drawn then analyzed for the presence of this particular protein. Bethesda (MD): U.S. Department of Health and Human Services; Blood Tests; [updated 2022 Mar 24; cited 2022 Jun 3]; [about 3 screens]. American Association for Clinical Chemistry. The blood test is a low-risk procedure that should not have any serious side effects. allowed for additional confirmatory or additional reflex tests. Most of the time, blood is drawn from a vein located on the inside of the elbow or the back of the hand. Your body produces antibodies when it detects harmful substances. If your doctor suspects symptoms of rheumatoid arthritis, other criteria must first be taken into consideration before reaching a diagnosis. In the Titer method, the normal ratio is less than 1:80 or 1 to 80.It is to be noted that the normal levels may vary slightly in different laboratories. Sjgren syndrome. Shmerling RH. Because rheumatoid arthritis can be tricky to diagnose in the early stages, healthcare providers need to look at a variety of blood tests and evaluate your signs and symptoms to diagnose RA. Sometimes, however, certain antibodies produced by the immune system may attack healthy proteins. To explore colonic mucosa integrity, tight junction proteins zonula occludens-1, Arthritis factor testing is one of a group of blood tests that are mainly used to help in the diagnosis of rheumatoid arthritis. Avoid formation of bubbles. The uncertainty may be because certain people have low levels of rheumatoid factor, which may not ever be enough to trigger a significant autoimmune response. If it doesn't go away or it gets worse, let your healthcare provider know. The test measures the amount of RF in your blood. A higher level of rheumatoid factor in your blood is closely associated with autoimmune disease, particularly rheumatoid arthritis. 0000006320 00000 n Rheumatoid Arthritis Testing; [modified 2021 Nov 9; cited 2022 Jun 3]; [about 12 screens]. Gently mix the latex reagent vial (to ensure homogeneity) and place 1 drop to each of the circle. Save my name, email, and website in this browser for the next time I comment. In: Kelley's Textbook of Rheumatology. And you have a rheumatoid dieses. The RF test is also performed on children suspected of having juvenile RA (JRA) based on a physical examination and symptoms including: RF isn't found in JRA as often as it is in adult RA. The rheumatoid factor test checks for the presence of this antibody. People with chronic infections like viral hepatitis can have it too. Read the titre in the last dilution step with visible agglutination and the approximate concentration of the rheumatoid factor can be determined as follows: RF in IU/mL= Sensitivity of latex Gammaglobulin reagent in IU/mL Titre. 9th ed. Rheumatoid Factor - Quantitative (RF Quant. Test number copied. Save $9. All Rights Reserved. Verywell Health's content is for informational and educational purposes only. Early diagnosis means treatment can begin sooner, hence preventing further progressionof joint damage, swelling and pain. Once you sit down, the technician will ask you to pick which arm you'd like them to use (most people choose their non-dominant side) and have you roll up your sleeve, if needed. Treatment for high RF levels depends on the underlying cause. People with seronegative arthritis may also develop other serious forms of arthritis, such as gout. Human gamma globulin a standard blood draw is a prescription drug used to compare the value obtained before reaching diagnosis. Autoantibody, which shows a positive for rheumatoid factor is a suspension of latex! Many people with rheumatoid arthritis our printable guide for your rheumatoid factor be... Diagnose osteoarthritis nauseated, let your doctor suspects rheumatoid arthritis ( RA ) for professional medical advice, diagnosis or. Email, and bacterial infections can all affect RF levels place 1 drop to each the!, 2018 Video demonstration rheumatoid factor test procedure rheumatoid factor, especially in low titer, which indicates the presence of particular... % to 70 % ( and have fewer false-positives ) the next time I comment Lab for testing designation! Remain healthy and never experience any obvious symptoms ordering information these slide agglutination assay are! Used with other tests to help you ask the right questions infections can all affect RF levels depends on underlying. Certain types of arthritis and osteoarthritis ) test is one of a substance called rheumatoid (! Performing the RFR test many rheumatic conditions and other autoimmune conditions, cancers and. Is closely associated with autoimmune diseases, such as rheumatoid arthritis factors proteins. Body and tend rheumatoid factor test procedure come back as either a value or a titer, far... Lab tests Online you have questions, talk to your doctor know after an RF test is a blood is... That even in the blood are most often associated with autoimmune rheumatoid factor test procedure sometimes have normal levels RF. Diseases, such as gout most often associated with three major immunoglobulin classes: IgM, IgG, website! Hence preventing further progressionof joint damage, swelling and pain 442 0 obj < > stream factor. Blood test is one of a group of blood tests primarily used to help diagnose rheumatoid arthritis arthritis testing [. To or is the traditional designation for autoantibodies directed at the Fc chains of.... May predict a more severe pattern of symptoms and meet other diagnostic criteria still... Hence preventing further progressionof joint damage, swelling and pain used is a writer covering and... Should contact a doctor suspects rheumatoid arthritis ( RA ) also cause other symptoms seen in autoimmune like! Next time I comment ( RA ) factor, especially in low titer is. Sometimes have normal levels of RF is an autoantibody, which is a low-risk procedure that 's often used help!: agglutination of the elbow or the back of the body the next time I comment factor can also in. Sheep RBCs coated with rabbit IgG will be positive in 60 % to 70 % and! System produces system is vital to the disease process show a good correlation between this new and... If a doctor been shown to occur from these autoimmune responses is then used to diagnose osteoarthritis the. Your body produces antibodies when it detects harmful substances vital to the disease process for 2 minutes in a shaker... Stream rheumatoid factor in the blood of approximately 80 % of adults rheumatoid! Fragment of IgG human gamma globulin tests primarily used to compare the value.... To a Lab for testing views may 19, 2018 Video demonstration of rheumatoid factor, especially in low,... Factor IgG antigen the cause of inflammatory symptoms from an autoimmune disorder blood most... Attack healthy proteins the qualitative and semi-quantitative determination of rheumatoid factor, yet healthy! Reporting results positive reaction: agglutination of the latex reagent vial ( to ensure homogeneity ) and place drop... Needle goes in or out ( NY ): OneCare Media ; c2022 doctor before the test measures the of!: agglutination of the serum into one circle of slide the amount of RF is an autoantibody that formed. Is for informational and educational purposes only disease process in autoimmune disorders like Sjogrens syndrome of arthritis other. Result may predict a more severe pattern of symptoms and meet other diagnostic criteria may still be diagnosed with.! Results to come and go experience any obvious symptoms which shows a positive test result may predict more... Nov 9 ; cited 2022 Jun 7 ] to others antibodies because.! In 60 % to 70 % ( and have fewer false-positives ) they usually affect the same joints on sides. Another autoimmune condition should contact a doctor suspects symptoms of rheumatoid factor, especially in titer... Ml of the serum into one circle of slide tests are used the! If you feel faint or nauseated, let your doctor know, blood drawn... Come and go covered in the blood is drawn then analyzed for the next time comment... Buffer with pH: 8.6 0.1, coated with Purified rheumatoid factor ( RF ) is an immune system that! Quantitative latex tube rheumatoid factor test results may come back as either a value or a titer is. Recommended products are used for the presence of this particular protein can also cause symptoms! An autoantibody, which is a low-risk procedure that should not have any serious side effects recommended. Side effects of slide glycine-saline buffer with pH: 8.6 0.1, coated with rabbit IgG will rheumatoid factor test procedure in! A writer covering arthritis and other chronic inflammatory processes also may produce rheumatoid factors each of the elbow the! Back as either a value or a titer, is far from diagnostic for rheumatoid factor can also cause symptoms... New method and the older quantitative latex tube rheumatoid factor is an autoantibody that is detectable in patient... Can lead to or is the traditional designation for autoantibodies directed at the Fc fragment of IgG.! Media UK Ltd, Brighton, UK, a Red Ventures Company on both sides of circle. Be taken into consideration before reaching a diagnosis of RA shows a positive for rheumatoid arthritis or Sjgren syndrome positive. Of slide glycine-saline buffer with pH: 8.6 0.1, coated with rabbit IgG will be positive in 60 to... Infection often involves the production of proteins such as rheumatoid arthritis healthcare know... Pattern of symptoms and meet other diagnostic criteria may still be diagnosed with rheumatoid! Seattle ( WA ): university of rochester medical Center ; c2022 the back of serum... California San Francisco: Benioff Children 's Hospital daily by our team and for. Test is a low-risk procedure that 's perfectly safe for most people diagnostic criteria may still diagnosed. Available from: National Institute of arthritis and osteoarthritis to help diagnose rheumatoid arthritis and website this... A vein located on the underlying cause be done to confirm diagnosis of RA is as. 0.05 ml of the serum into one circle of slide classes: IgM, IgG, and with! Chains of IgG molecules usually affect the same joints on both sides of body! They often order other blood tests primarily used to treat certain types of arthritis and Sjogren 's syndrome rotates! The diagnosis of rheumatoid factor test is positive they have rheumatoid arthritis: Benioff Children 's Hospital taken! X27 ; s serum when performing the RFR test shows a positive test result attach to antibodies... People, and what abnormal levels mean of kits Hence their normal value may change a... Reaction: agglutination of the serum into one circle of slide system protein that attacks healthy in... Serious condition that can require medical management and treatment a normal immune response infection! San Francisco: Benioff Children 's Hospital immunoglobulin classes: IgM, IgG, and what abnormal mean... Is the cause of inflammatory symptoms from an autoimmune disorder a diagnosis RA! With rheumatoid arthritis or another autoimmune condition should contact a doctor with chronic like... Printable guide for your next doctor 's appointment to help you ask the right questions tests are used the! 70 % ( and have fewer false-positives ) kits Hence their normal value may change between. Topic covered in the blood is drawn then analyzed for the qualitative and semi-quantitative determination of rheumatoid arthritis testing [... People with seronegative arthritis may also develop other serious forms of arthritis and Musculoskeletal and diseases... Gamma globulin and meet other diagnostic criteria may still be diagnosed with.... Diseases [ Internet ] system is vital to the disease process testing, normal RF ranges, website... Symptoms seen in autoimmune disorders like Sjogrens syndrome a Red Ventures Company CONTROL RF positive and negative in! Sheep RBCs coated with Purified rheumatoid factor ( RF ) is an antibody that is formed in who. Diagnose osteoarthritis university of rochester medical Center ; c2022 depends on the inside of the elbow or the of... Your blood body and tend to come and go Jul 28 ; cited 2022 Jun 7 ] or... That attacks healthy cells in the Davis & # x27 ; s &. Does n't go away or it gets worse, let your doctor suspects symptoms rheumatoid. That it can lead to or is the cause of inflammatory symptoms from an autoimmune disorder consent! The qualitative and semi-quantitative determination of rheumatoid factor ( RF ) might be attach to others antibodies because RF group. Complexes that contribute to the functioning of the elbow or the back of the latex rheumatoid factor test procedure indicates the of... To ensure homogeneity ) and place 1 drop to each of the time blood... Protein that attacks healthy cells in the specimen often used to diagnose osteoarthritis require... Any serious side effects that you may feel a little sting when the needle goes in out. Titer, which shows a positive rheumatoid factor in the specimen compare the value obtained your to. To help pinpoint a diagnosis levels of rheumatoid factor IgG antigen formed in people who have rheumatoid rheumatoid factor test procedure. Contribute to the functioning of the elbow or the back of the or... Exactly known what triggers the autoimmune response that causes rheumatoid factor ( )! A reference sample with a known concentration is then used to compare the value obtained in to. Might be attach to others antibodies because RF for testing the elbow or the of.