Table 1.

Initial criteria, their respective categories, and initial weights assigned to each category^*

Criterion and category	Score
Joint involvement (pattern and distribution)
1 medium-large joint	0.0
Asymmetric medium-large joints (at least 2 joints)	12.3
Symmetric medium-large joints (at least 2 joints)	20.0
1–3 small joints (hands/feet or wrists)	26.2
≥4 asymmetric small joints (hands/feet or wrists)	35.4
≥4 symmetric small joints (hands/feet or wrists)	36.9
Serology (ACPA or RF)
RF negative and ACPA negative	0.0
Low-positive (RF positive and/or ACPA positive)	27.0
High-positive (RF positive and/or ACPA positive)	43.1
Acute-phase reactants (CRP or ESR)
Normal	0.0
Abnormal	7.7
Duration of synovitis
<4 weeks	0.0
4–8 weeks	10.8
>8 weeks	12.3

^*Scores from each criterion are summed to derive the total score, which represents the probability of developing rheumatoid arthritis (RA).

ACPA = anti–cyclic citrullinated protein; RF = rheumatoid factor; CRP = C-reactive protein; ESR = erythrocyte sedimentation rate.