Nell et al developed a decision tree based on serologic testing that can identify a patient with early arthritis who is at risk for developing rheumatoid arthritis (RA) with erosive disease. This can help identify patients who may benefit from closer monitoring and more aggressive management. The authors are from the University of Vienna.
Serologic tests:
(1) rheumatoid factor (RF) in U per mL (> 20 U/mL positive)
(2) antibodies to cyclic citrullinated peptide (anti-CCP, positive if > 5 arbitrary units)
(3) anti-RA33 (targets ribonucleoprotein A2)
Time of initial assessment: < 3 months since onset of symptoms
RF |
Anti-CCP |
Anti-RA33 |
Final Diagnosis RA |
>= 50 U/mL |
NA |
NA |
45%, high risk of developing RA, high risk erosive disease |
< 50 U/mL |
positive |
NA |
14%, high risk of developing RA, high risk erosive disease |
< 50 U/mL |
negative |
positive |
13%, moderate risk of developing RA, good prognosis |
< 50 U/mL |
negative |
negative |
28%, low risk of developing RA, excellent prognosis |
RF |
Anti-CCP |
Anti-RA33 |
Final Diagnosis not RA |
>= 50 U/mL |
NA |
NA |
4%, |
< 50 U/mL |
positive |
NA |
2% |
< 50 U/mL |
negative |
positive |
9% |
< 50 U/mL |
negative |
negative |
85% |
Performance
Test |
Sensitivity for RA |
Specificity for RA |
---|---|---|
RF positive (> 20 U/mL) |
55% |
89% |
RF high titer (>= 50 U/mL) |
45% |
96% |
anti-CCP positive |
41% |
98% |
anti-RA33 |
28% |
90% |
Purpose: To evaluate a patient with early rheumatoid arthritis for the risk
Specialty: Immunology/Rheumatology
Objective: risk factors, severity, prognosis, stage
ICD-10: M05, M06,