title: Anti-cyclic citrullinated peptide antibody is a good indicator for the diagnosis of rheumatoid arthritis.
abstract: OBJECTIVE
  Anti-cyclic citrullinated peptide (CCP) antibody has recently been used in the classification of rheumatoid arthritis (RA). This antibody is more specific than rheumatoid factor (RF) for the diagnosis of RA. The study objectives were to determine the sensitivity, specificity, positive and negative predictive values of anti-CCP in RA diagnosis.
  
  
  METHODS
  Eighty RA patients and 80 non-RA individuals were included in the study. Blood was collected from both arms of study subjects and tested for anti-CCP and RF antibodies. Relevant clinical information and laboratory profiles of the RA patients were evaluated using patients' medical records and Integrated Laboratory Management System (ILMS), respectively. Results : The sensitivity and specificity of anti-CCP were 35% and 100% respectively. The positive and negative predictive values were 100% and 61%, respectively. Positive anti-CCP was found significantly associated with multiple joint pain (p< 0.001) and hand's joints pain (p=0.01), symmetrical joints involvement (p=0.015) and high CRP value (p<0.001). Anti-CCP was also found to have positive association with RF (p<0.001).
  
  
  CONCLUSIONS
  Anti-CCP is highly specific for the diagnosis of RA. High positive predictive value should be taken into consideration for effective treatment.
authors.affiliation: Asrul Abdul Wahab, Department of Medical Microbiology & Immunology, Faculty of Medicine, The National University of Malaysia, Cheras 56000 Kuala Lumpur, Malaysia.
authors.forename: Asrul
authors.initials: A
authors.lastname: Abdul Wahab
authors.affiliation: Marlyn Mohammad, Department of Medical Microbiology & Immunology, Faculty of Medicine, The National University of Malaysia, Cheras 56000 Kuala Lumpur, Malaysia.
authors.forename: Marlyn
authors.initials: M
authors.lastname: Mohammad
authors.affiliation: M.M. Rahman, Department of Medical Microbiology & Immunology, Faculty of Medicine, The National University of Malaysia, Cheras 56000 Kuala Lumpur, Malaysia.
authors.forename: M M
authors.initials: MM
authors.lastname: Rahman
authors.affiliation: Mohd. Shahrir Mohamed Said, Department of Internal Medicine, Faculty of Medicine, The National University of Malaysia, Cheras 56000 Kuala Lumpur, Malaysia.
authors.forename: Mohd Shahrir
authors.initials: MS
authors.lastname: Mohamed Said
keywords: Negative predictive value; Positive predictive value; Rheumatoid arthritis; Rheumatoid factor; Sensitivity; Specificity; anti-CCP