From the Guidelines
Laboratory tests for Sjögren's syndrome should include anti-Ro/SSA and anti-La/SSB antibodies, antinuclear antibody (ANA), and rheumatoid factor (RF), as these are the most relevant markers for diagnosis, as indicated by the latest guidelines 1. When evaluating patients for Sjögren's syndrome, it is essential to consider a combination of clinical findings and laboratory results, as no single test is definitive.
- Blood tests often include:
- Antinuclear antibody (ANA)
- Anti-Ro/SSA and anti-La/SSB antibodies, which are present in many Sjögren's patients
- Rheumatoid factor (RF) and erythrocyte sedimentation rate (ESR) or C-reactive protein (CRP) to assess inflammation
- Complete blood count to detect anemia or other blood abnormalities
- Immunoglobulin levels, which are often elevated in Sjögren's
- Specific tests for salivary gland function include:
- Sialometry (measuring saliva production)
- Sialography (imaging salivary ducts)
- A salivary gland biopsy, particularly of minor salivary glands from the inner lip, is considered the gold standard for diagnosis, showing characteristic lymphocytic infiltration, as supported by recent studies 1.
- Ocular tests like Schirmer's test (measuring tear production) and ocular surface staining may be performed to assess eye dryness. These tests collectively help diagnose Sjögren's syndrome and distinguish it from other conditions with similar symptoms. According to the latest classification criteria, the diagnosis of primary Sjögren's syndrome is based on the weighted sum of five items, including anti-SSA/Ro antibody positivity, focal lymphocytic sialadenitis, abnormal ocular staining score, Schirmer test result, and unstimulated salivary flow rate, as outlined in the study 1.
From the Research
Sjögren's Disease Laboratory Tests
- Laboratory tests for Sjögren's disease include serologic testing, which reveals antinuclear auto-antibodies (anti-Ro/ SSA and anti-La/SSB) as well as rheumatoid factors 2.
- Anti-SSA/Ro and anti-La/SSB antibodies are the hallmark antibodies in primary Sjögren's syndrome (pSS), being present in 60-70% of patients 3.
- These antibodies have been associated with an earlier disease onset, glandular dysfunction, and extraglandular manifestations, as well as with other B cells activation markers 3.
- The presence of anti-Ro/SSA and anti-La/SSB antibodies is useful in the diagnosis of pSS and helps to identify more "active" patients 3.
Autoantibodies in Sjögren's Syndrome
- A large number of autoantibodies have been detected in the serum of patients with primary Sjögren's syndrome (pSS) 4.
- Among them, anti-Ro/SSA and anti-La/SSB autoantibodies are the most common and serve as disease markers 4.
- Other autoantibodies are associated with significant clinical phenotypes, such as cryoglobulins with development of non-Hodgkin's lymphoma, anti-centromere antibodies with Raynaud's phenomenon, and anti-mitochondrial antibodies with liver pathology 4.
Clinical Presentation of Anti-SSA/SSB Antibody Double-Negative Sjögren's Disease
- Anti-Sjögren's syndrome A (SSA/Ro60) and anti-Sjögren's syndrome B (SSB/La) antibodies are not present in up to 25% of patients with primary Sjögren's disease (SjD) 5.
- Anti-SSA/SSB seronegative patients have a delayed onset of disease and exhibit a lower prevalence of parotid gland enlargement compared to the seropositive group 5.
- The double-negative group tends to have higher CD4+ T helper cells and lower CD8+ T cell proportions compared with the anti-SSA/SSB-positive group 5.
Clinical Practice Guideline for Sjögren's Syndrome
- The clinical practice guideline (CPG) for Sjögren's syndrome (SS) was developed based on recently available clinical and therapeutic evidences 6.
- The CPG committee set 38 clinical questions for clinical symptoms, signs, treatment, and management of SS in pediatric, adult, and pregnant patients 6.
- The CPG for SS 2017 should contribute to improvement and standardization of diagnosis and treatment of SS 6.