Type of test Blood

 Normal findings

 Negative (< 60 units/mL by nephelometric testing)

(Elderly patients may have slightly increased values.)

Test explanation and related physiology

In rheumatoid arthritis (RA), abnormal immunoglobulin G (IgG) antibodies produced by lymphocytes in the synovial mem branes act as antigens. Other IgG and IgM antibodies in the patient’s serum react with the fc component of the abnormal synovial antigenic IgG to produce immune complexes. These immune complexes activate the complement system and other inflammatory systems to cause joint damage. The reactive IgM is called RF. Tissues other than the joints, including those of the blood vessels, lungs, nerves, and heart, may also be involved in the autoimmune inflammation.

Tests for RF are directed toward identification of the IgM antibodies. Approximately 80% of patients with RA have positive RF titers. To be considered positive, RF must be found in a dilution of greater than 1:80; when RF is found in titers less than 1:80, such diseases as systemic lupus erythematosus, scleroderma, and other autoimmune conditions should be considered. Although the normal value is “no rheumatoid factor identifiable at low titers,” a small number of normal patients will have RF present at a very low titer. Furthermore, a negative RF does not exclude the diagnosis of RA. RF is not a useful disease marker because its presence does not disappear in patients who are experiencing a remission from the disease symptoms.

Other autoimmune diseases such as systemic lupus erythematosus and Sjögren syndrome also may cause a positive RF test. RF is occasionally seen in patients with tuberculosis, chronic hepatitis, infectious mononucleosis, and subacute bacterial endocarditis as well.

Interfering factors

• Elderly patients often have false-positive results.

• Hemolysis or lipemia may be associated with false-positive results.

Procedure and patient care

 • See inside front cover for Routine Blood Testing.

• Fasting: no

 • Blood tube commonly used: red

Abnormal findings

 Increased levels

- RA

- Other autoimmune diseases (e.g., systemic lupus erythematosus)

-  Chronic viral infection

- Subacute bacterial endocarditis

- Tuberculosis

- Chronic hepatitis

- Dermatomyositis

- Scleroderma Infectious mononucleosis

- Leukemia

- Cirrhosis

- Syphilis

- Renal disease

اخر الاخبار

اخبار العتبة العباسية المقدسة

فرقة العباس تنظم مجلس عزائها السنوي بذكرى شهادة النبي (صلى الله عليه وآله) في النجف

قسم الشؤون الفكرية وجامعة الكوفة يعقدان شراكة علمية لتدريب الطلبة على صيانة المخطوطات وحفظها

بالتزامن مع ذكرى شهادته.. قسم الشؤون الفكرية يصدر كتابًا عن النبي الأعظم (صلى الله عليه وآله)

بالصور.. جموع المؤمنين تحيي ذكرى شهادة الرسول الأكرم عند مرقد الإمام علي (صلوات الله عليهما)

المزيد

الآخبار الصحية

لون أسنانك يتحدث عن صحتك.. إليك ما يقول

عادة يومية بسيطة تخفض الكوليسترول وتحمي القلب

الزنجبيل.. دواء سحري لحماية القلب

المشروبات شديدة السخونة.. "خطر خفي" يهدد صحتك

المزيد

الآخبار التكنلوجية

كيف يمكن لعادات القيادة السيئة أن تؤثر على قيمة سيارتك

في طوفان الذكاء الاصطناعي.. نصائح لحجز "تذكرة النجاة"

هكذا يسرق "قراصنة الذكاء الاصطناعي" المليارات بطرق بسيطة

فيديو لانفجار كرة نارية في سماء اليابان.. ما تفسير ذلك؟

المزيد

مواضيع ذات صلة

reticulocyte count (Retic count)

red blood cell indices (RBC indices, Blood indices)

NGAL

Biomarkers of Tubulo-Interstitial Injury

Low-Molecular-Weight Plasma Proteins

Immunofluorescence Assay (IFA)

Enzyme-Linked Fluorescent Assay (ELFA)

Diagnostic Evaluation of Lyme disease

red blood cell count (RBC count, Erythrocyte count)

rabies-neutralizing antibody test

prothrombin time (PT, Protime, International normalized ratio [INR])

Estimation of the Glomerular Filtration Rate by Equations