From the Guidelines
For suspected Sjögren's syndrome and SLE, initial tests should include antinuclear antibody (ANA), complete blood count (CBC), comprehensive metabolic panel, erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP).
Initial Tests
For Sjögren's specifically, order anti-SSA/Ro and anti-SSB/La antibodies, rheumatoid factor (RF), and consider Schirmer's test and salivary gland biopsy if symptoms warrant.
- Anti-SSA/Ro and anti-SSB/La antibodies are crucial for diagnosing Sjögren's syndrome, as they are commonly found in patients with this condition 1.
- Rheumatoid factor (RF) can also be present in Sjögren's syndrome, although it is not specific to this disease.
Additional Tests for SLE
For SLE, include anti-double stranded DNA (anti-dsDNA), anti-Smith antibodies, complement levels (C3, C4), urinalysis, and anti-phospholipid antibodies.
- Anti-dsDNA antibodies are highly specific for SLE and can be used to monitor disease activity 1.
- Complement levels (C3, C4) can also be useful in monitoring SLE activity, as low levels can indicate active disease.
- Urinalysis can detect renal involvement, which is common in SLE.
Importance of Early Diagnosis
These tests help establish diagnosis based on specific autoantibody patterns and organ involvement.
- ANA serves as a screening test for both conditions, with positive results warranting more specific antibody testing 1.
- The CBC may reveal cytopenias common in SLE, while urinalysis can detect renal involvement.
- Early diagnosis is crucial as both conditions can lead to significant organ damage if left untreated, and treatment strategies differ based on disease manifestations and severity.
- Regular monitoring of patients with SLE is also important to prevent complications, such as cardiovascular disease and infections 1.
From the Research
Initial Tests for Sjögren's Syndrome and Systemic Lupus Erythematosus (SLE)
The initial tests to order for Sjögren's syndrome and Systemic Lupus Erythematosus (SLE) include:
- Traditional biomarkers such as anti-Sjögren's syndrome-related antigen A (SS-A/Ro), anti-Sjögren's syndrome-related antigen B (SS-B/La), antinuclear antibody (ANA) titers, and rheumatoid factor (RF) 2
- Novel biomarkers including autoantibodies to proteins specific to the salivary and lacrimal glands such as SP-1, PSP, and CA-6 2
- IgA autoantibodies to Ro 52 kDa, Ro 60 kDa, and La antigen, which are detected at high frequency in patients with SLE and Sjögren's syndrome 3
- Anti-Ro/SS-A and anti-La/SS-B antibodies, which are more frequently found in patients with associated SLE and Sjögren's syndrome 4
- Anti-SSB antibodies, which have a high specificity for diagnosing SLE and are associated with certain clinical manifestations such as cheek erythema, alopecia, and serositis 5
Laboratory Evaluations
Laboratory evaluations for Sjögren's syndrome and SLE may include:
- Counterimmunoelectrophoresis to determine anti-Ro/SS-A antibody titers 6
- Immunoblotting to determine the fine specificity of anti-Ro antibodies 6
- Line immunoassay (LIA) to detect the presence of serum anti-SSB antibodies 5
- Semiquantitative immunoblotting approach to analyze autoantibodies in serum 3
Clinical Considerations
Clinical considerations for diagnosing Sjögren's syndrome and SLE include:
- Dry eye and dry mouth as the earliest presenting complaints 2
- Joint and muscle pain, skin rashes, chronic dry cough, vaginal dryness, extremity numbness or tingling, and disabling fatigue as possible symptoms 2
- Presence of rheumatoid factor, antinuclear antibody, and anti-DNA autoantibodies 4
- Pulmonary, renal, skin, central nervous system involvement, and serositis as more frequent in patients with associated SLE and Sjögren's syndrome 4