In the "new" criteria, serology and autoimmune diagnostics carries major weight, as ACPA detection is appropriate to diagnose the disease in an early state, before joints destructions occur. Destruction of the joints viewed in radiological images was a significant point of the ACR criteria from 1987. This criterion no longer is regarded to be relevant, as this is just the type of damage that treatment is meant to avoid. Differential diagnoses
Several other medical conditions can resemble RA, and need to be distinguished from it at the time of diagnosis:
Crystal induced arthritis (gout, and pseudogout) – usually involves particular joints (knee, MTP1, heels) and can be distinguished with an aspiration of joint fluid if in doubt. Redness, asymmetric distribution of affected joints, pain occurs at night and the starting pain is less than an hour with gout. Osteoarthritis – distinguished with X-rays of the affected joints and blood tests, older age, starting pain less than an hour, asymmetric distribution of affected joints and pain worsens when using joint for longer periods. Systemic lupus erythematosus (SLE) – distinguished by specific clinical symptoms and blood tests (antibodies against double-stranded DNA)
One of the several types of psoriatic arthritis resembles RA – nail changes and skin symptoms distinguish between them
Lyme disease causes erosive arthritis and may closely resemble RA – it may be distinguished by blood test in endemic areas
Reactive arthritis – asymmetrically involves heel, sacroiliac joints and large joints of the leg. It is usually associated with urethritis, conjunctivitis, iritis, painless buccal ulcers, and keratoderma blennorrhagica.
Curious fact is that only responder patients showed an increase in those miRNAs after therapy, and paralleled the reduction of TNFα, interleukin (IL)-6, IL-17, rheumatoid factor (RF), and C-reactive protein (CRP). Monitoring progression
Many tools can be used to monitor remission in rheumatoid arthritis. DAS28: Disease Activity Score of 28 joints (DAS28) is widely used as an indicator of RA disease activity and response to treatment. Joints included are (bilaterally): proximal interphalangeal joints (10 joints), metacarpophalangeal joints (10), wrists (2), elbows (2), shoulders (2) and knees (2). When looking at these joints, both the number of joints with tenderness upon touching (TEN28) and swelling (SW28) are counted. The erythrocyte sedimentation rate (ESR) is measured and the affected person makes a subjective assessment (SA) of disease activity during the preceding 7 days on a scale between 0 and 100, where 0 is "no activity" and 100 is "highest activity possible".