0 points Low-positive RF or low-positive ACPA gives 2 points High-positive RF or high-positive ACPA gives 3 points acute phase reactants: 1 point for elevated erythrocyte sedimentation rate, ESR, or elevated CRP value (c-reactive protein) duration of arthritis: 1 point for symptoms lasting six weeks or longer The new criteria accommodate to the growing understanding of RA and the improvements in diagnosing RA and disease treatment. 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. Axial spondyloarthritis (including ankylosing spondylitis) – this involves the spine, although an RA-like symmetrical small-joint polyarthritis may occur in the context of this condition. Hepatitis C – RA-like symmetrical small-joint polyarthritis may occur in the context of this condition. Hepatitis C may also induce rheumatoid factor auto-antibodies. Rarer causes which usually behave differently but may cause joint pains: Sarcoidosis, amyloidosis, and Whipple's disease can also resemble RA. Hemochromatosis may cause hand joint arthritis. Acute rheumatic fever can