New Diagnostic Criteria

Change is in the wind.  Until now, the ACR’s diagnostic criteria for RA has been any four of the following:

1. Morning stiffness, lasting for at least an hour, present daily for at least 6 weeks
2. Arthritis of 3 or more joints, lasting for at least 6 weeks
3. Arthritis of the hand joints, lasting for at least 6 weeks
4. Symmetric arthritis, lasting for at least 6 weeks
5. Rheumatoid nodules
6. Positive rheumatoid factor (blood test)
7. Joint changes on x-ray

Recently, the American College of Rheumatology collaborated with the European League Against Rheumatism to re-define diagnostic criteria.  Instead of needing to see evidence of long-term damage, the goal will be to treat RA aggressively enough that damage doesn’t occur. 

Now, instead of the aforementioned criteria, there is a scoresheet that looks at joint involvement, serology, duration of synovitis, and acute phase reactants:

Joint Involvement

• 1 med-large joint (0 points)
• 2-10 med-lg joints (1 point)
• 1-3 small joints (2 points)
• 4-10 small joints (3 points)
• >10 joints (at least one small joint) (5 points)

Serology

• Neither RF or ACPA positive (0 points)
• At least one test low positive titer (2 points)
• At least one test high positive titer (3 points)

Duration of Synovitis

• <6 weeks (0 points)
• >6 weeks (1 point)

Acute Phase Reactants

• Neither ESR nor CRP abnormal (0 points)
• Abnormal CRP or abnormal ESR (1 point)

Total score of six or more points means a definite RA diagnosis, even without x-ray evidence.  Doctors aren’t limited by normal sed rate, CRP, or RF.  A zillion joints involved for six or more weeks equates to a positive diagnosis without it mattering one bit what any lab results might say.

Patients can read more about it here.

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ACPA = anti-cyclic citrullinated peptide antibody (ie, anti-CCP test)