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Autoimmune Diagnostics

Differential Diagnosis of Rheumatoid Diseases

Differential diagnosis of rheumatoid diseases for example is based on a huge arsenal of methods for the detection of numerous different autoantibodies. The figure below shows a schematic representation of the sequence of different blood tests for differential diagnosis of rheumatoid arthritis (RA).

Fig.1
Detection of autoantibodies for differential diagnosis of rheumatoid arthritis after clinical suspicion of the disease
© Orgentec Diagnostika

Clinical suspicion is based on the criteria for the classification of rheumatoid arthritis published by the American College of Rheumatology (ACR)1,, first published in 1987, which have recently been updated by a joint working group from the ACR and the European League Against Rheumatism (EULAR)2).

The new classification system is focusing on features at earlier stages that are associated with more severe disease rather than defining the disease by its late-stage features. This will enable clinical researchers to study treatments for rheumatoid arthritis at earlier stages, before joint damage occurs, ultimately leading to better patient outcomes.

Tab.1
Classification criteria for diagnosis of rheumatoid arthritis
1987 American College of Rheumatology (ACR) criteria for the diagnosis of rheumatoid arthritis 2010 ACR-EULAR classification criteria for rheumatoid arthritis
Target Population: Patients with definite clinical synovitis in at least one joint, with no alternative diagnosis better explaining the synovitis. Score
# Morning stiffness lasting at least one hour A. Joint involvement
# Arthritis in three or more joints 1 large joint 0
# Arthritis of the small joints of fingers or wrists 2-10 large joints 1
# Symmetric arthritis 1-3 small joints (with or without involvement of large joints) 2
# Rheumatoid nodules 4-10 small joints (with or without involvement of large joints) 3
# positive rheumatoid factor > 10 joints (at least one small joint) 5
# Medical imaging shows characteristic deformities and abnormalities B. Serology     (at least one result is needed for classification)
Negative RF3) and negative ACPA 0
Low-positive RF or low-positive ACPA 2
High positive RF or high positive ACPA 3
C. Acute phase reactants     (at least one result is needed for classification)
Normal CRP and normal ESR 0
Abnormal CRP4) or abnormal ESR5) 1
D. Duration of symptoms
< 6 weeks 0
> 6 weeks 1
Cut off: ≥ 6 points define definite rheumatoid arthritis

Table as graphic representation

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