RHEUMATOID ARTHRITIS-INVESTIGATIONS

SUMMARY

1. Rheumatoid factor (RF) is positive in only 80-85% of patients with RA. It may take up to 2 years to become RF positive.

2. RF is positive in major chronic non-rheumatic diseases: infections (TB, syphilis, hepatitis), pulmonary (sarcoidosis, ILD, silicosis) & miscellaneous diseases (malignancy).

3. Anti-CCP antibody appears earlier than RF, has greater specificity (97%), is associated with more aggressive disease and extra-articular involvement.

4. A high titer of either RF or anti-CCP contributes 3 of the 6 points required for the diagnosis.

5. RF (+) is associated with increased severity of disease with increased systemic manifestation (extra-articular features).

6. RF (+) can be seen in other diseases: rheumatic (SLE, scleroderma, Sjögren's), viral, parasitic, bacterial, neoplasms.

Reference(s)

Wilkinson, I., Furmedge, D. and Sinharay, R. (2017). Oxford handbook of clinical medicine. Oxford: Oxford University Press. Get it on Amazon.
Feather, A., Randall, D. and Waterhouse, M. (2020). Kumar And Clark’s Clinical Medicine. 10th ed. S.L.: Elsevier Health Sciences. Get it on Amazon.
Hannaman, R. A., Bullock, L., Hatchell, C. A., & Yoffe, M. (2016). Internal medicine review core curriculum, 2017-2018. CO Springs, CO: MedStudy.
Therapeutic Guidelines. Melbourne: Therapeutic Guidelines Limited. https://www.tg.org.au [Accessed 2021].