Detection of autoantibodies directed against cell nucleus components using indirect immunofluorescence on HEp-2 cells. ANA are the first-line screening markers for connective tissue diseases. The fluorescence pattern helps guide the diagnosis toward the type of disease.

• Screening for connective tissue diseases (lupus, scleroderma, Sjögren's syndrome)
• Diagnostic orientation based on titer and fluorescence pattern

Venous blood

No specific preparation required.

• Inflammatory polyarthralgia
• Photosensitive skin rash (lupus)
• Raynaud's syndrome
• Sicca syndrome

Anti-ADN natif • Anti-ENA • Complément C3/C4 • VS • CRP

Detection of autoantibodies directed against enzymes in the cytoplasm of neutrophil granulocytes, using IIF followed by ELISA. Two types are distinguished: c-ANCA (anti-PR3) and p-ANCA (anti-MPO), associated with necrotizing vasculitis.

• Diagnosis of ANCA-associated vasculitis
• Differentiation between types of vasculitis
• Monitoring of disease activity

Venous blood

No specific preparation required.

• Rapidly progressive glomerulonephritis
• Hemoptysis with renal involvement
• Recurrent destructive sinusitis
• Vascular purpura

Créatinine • FNS • CRP • Complément • ECBU

Quantification of rheumatoid factors, autoantibodies mainly of IgM class directed against the Fc fragment of IgG. Classic markers of rheumatoid arthritis but non-specific.

• Aid in the diagnosis of rheumatoid arthritis
• ACR/EULAR classification criterion
• Prognostic evaluation

Venous blood

No specific preparation required.

• Bilateral and symmetrical polyarthritis
• Prolonged morning stiffness
• Rheumatoid nodules

Anti-CCP • VS • CRP • FNS • Radiographies articulaires

Quantification of antibodies directed against cyclic citrullinated peptides. Anti-CCP antibodies are highly specific for rheumatoid arthritis (specificity > 95%) and are present from the early stages.

• Early diagnosis of rheumatoid arthritis
• Diagnostic confirmation when RF is negative
• Prognostic factor (risk of erosions)

Venous blood

No specific preparation required.

• Recent polyarthritis suggestive of rheumatoid arthritis
• Negative RF with strong clinical suspicion
• Assessment of erosive disease risk

Facteurs rhumatoïdes • VS • CRP • FNS • AAN

Detection of autoantibodies directed against membrane phospholipids (anti-cardiolipin, anti-β2GP1, lupus anticoagulant). Associated with antiphospholipid syndrome (APS).

• Diagnosis of antiphospholipid syndrome (APS)
• Investigation of recurrent thrombosis
• Workup for recurrent miscarriages

Venous blood

No specific preparation required.

• DVT or PE without triggering factor
• Stroke in a young patient
• Late miscarriages
• Unexplained prolonged aPTT

TP • TCA • D-dimères • AAN • Anti-ADN • Complément

Detection of the HLA B27 antigen by flow cytometry or molecular biology. Strongly associated with spondyloarthropathies, particularly ankylosing spondylitis.

• Aid in the diagnosis of ankylosing spondylitis
• Guidance in cases of inflammatory lower back pain
• Family screening

Venous blood (EDTA tube)

No specific preparation required.

• Inflammatory lower back pain in young patients
• Radiological sacroiliitis
• Recurrent acute anterior uveitis
• Family history of spondyloarthropathy

CRP • VS • Radiographies du bassin/rachis • IRM des sacro-iliaques

Workup including screening for HLA-DQ2 and HLA-DQ8 genes and quantification of specific antibodies — anti-transglutaminase IgA, anti-endomysium and anti-gliadin. Celiac disease is an autoimmune enteropathy triggered by gluten.

• Serological diagnosis of celiac disease
• Screening in at-risk individuals
• Disease exclusion
• Monitoring adherence to gluten-free diet

Venous blood

The patient must be consuming gluten at the time of sampling. Total IgA measurement is essential.

• Chronic diarrhea with malabsorption
• Refractory iron deficiency anemia
• Growth retardation in children
• Dermatitis herpetiformis
• Family screening

IgA totales • FNS • Fer sérique • Ferritine • Vitamine B12 • Folates • Calcémie

Technique for separating serum proteins by electrophoretic migration, visualizing 5 fractions. A screening test for dysglobulinemias and inflammatory conditions.

• Detection of a monoclonal spike
• Evaluation of chronic inflammatory syndrome
• Screening for immunoglobulin deficiency
• Investigation of nephrotic syndrome

Venous blood

No specific preparation required.

• Unexplained very high ESR
• Diffuse bone pain in elderly patients
• Recurrent infections
• Bence-Jones proteinuria
• Unexplained hypercalcemia

Immuno-fixation • Immunoglobulines • Protéinurie • Calcémie • Créatinine

Immunochemical technique for characterizing a monoclonal immunoglobulin detected on SPE. Identifies the heavy chain isotype and the light chain type of the monoclonal component.

• Typing of a monoclonal spike
• Diagnosis of myeloma, Waldenström's macroglobulinemia, AL amyloidosis
• Monitoring treatment response

Venous blood

No specific preparation required.

• Monoclonal spike on SPE
• Suspected multiple myeloma
• Monitoring of MGUS

EPP • Immunoglobulines • Calcémie • Créatinine • β2-microglobuline • FNS

Quantification of specific IgE directed against common respiratory allergens — pollens, dust mites, animal dander, molds. Allows identification of sensitizations responsible for respiratory symptoms.

• Identification of allergens responsible for rhinitis, asthma or conjunctivitis
• Guidance for avoidance measures and desensitization
• Confirmation of sensitization

Venous blood

No need to stop antihistamines (unlike skin prick tests).

• Seasonal or perennial rhinitis
• Allergic asthma
• Allergic conjunctivitis
• Workup before desensitization
• Atopic eczema with respiratory component

IgE totales • FNS • Prick tests • Spirométrie

Quantification of specific IgE directed against common food allergens — milk proteins, egg, peanut, tree nuts, shellfish, fish, wheat, soy. Essential for diagnosing IgE-mediated food allergies.

• Diagnosis of IgE-mediated food allergies
• Identification of the responsible allergen
• Assessment of anaphylaxis risk
• Monitoring of tolerance acquisition

Venous blood

No specific preparation required.

• Urticaria, angioedema after ingestion
• Food-related anaphylaxis
• Infant eczema with suspected milk allergy
• Oral allergy syndrome (cross-reactivity)
• Monitoring tolerance acquisition in children

IgE totales • FNS • Tests de provocation orale