Immunology testing

A number of immunology tests are available to GPs. A positive test is significant only if the individual has symptoms.

Symptoms	Tests to consider	Likely Rheumatic Condition	Comment
Inflammatory joint symptoms- pain, joint swelling, significant morning stiffness (>30-45min)	CCP	Rheumatoid arthritis (RA)	A positive CCP may be observed in healthy individuals without joint symptoms. It is not a diagnostic test for RAA negative CCP does not exclude RA
Sicca symptoms arthralgia/arthritis	ENA Rheumatoid factor	Sjogren’s Syndrome	Antibodies to Ro and La often observed in Sjogren’s
Muscle weaknessRaised CKSwallowing difficulty	ANA,ENA	Dermatomyositis/polymyositis	Inflammatory markers usually raisedSignificant CK rise( see myositis page)
Arthritis/arthralgiaPhotosentivityMalar rashMouth ulcersHair lossPleuritic chest pain Cytopenias	ANA,ENA	Lupus	A positive ANA can be seen in 30% of healthy people and is not diagnostic of SLE or other CTD. ANA should not be used to as a screening tool.
Secondary Raynaud’s Dyspnoea (ILD)SclerodactylyHeartburnTelangiectasia	ENA ANA	Systemic Sclerosis	Inflammatory markers often normal
Recurrent unexplained miscarriagesunexplained thromoembolic events	Lupus anticoagulant & anticardiolipin antibodies	Antiphospholipid syndrome	Haematology
Generally unwellPurpuric rashProteinuriaunexplained respiratory	ANCA	Systemic Vasculitis	Inflammatory markers raised

M.A & H.B/S.R 25-01-24

Antibody testing should not be used as a screening test for rheumatological disorders. A good history will guide the tests undertaken. These conditions are managed by various specialities and symptoms/signs will also direct referral.

Who to refer:

Only patients who have symptoms suggestive of an autoimmune inflammatory disorder
If patient has clinical symptoms of an inflammatory arthritis, please refer straightaway instead of waiting for immunology