Sjögren’s syndrome is an autoimmune disorder that affects the moisture-producing glands in the body. The most common symptoms are dry eyes, dry mouth, fatigue, and joint pain. Sjögren’s syndrome can occur alone (primary Sjögren’s syndrome) or develop in association with another autoimmune disease like rheumatoid arthritis or lupus (secondary Sjögren’s syndrome).
Quick Summary
There is no single definitive blood test that can diagnose Sjögren’s syndrome. However, blood tests can help support a diagnosis when used along with a person’s signs and symptoms and results of imaging and other tests. Some of the blood tests that may be useful include:
- Complete blood count (CBC)
- Erythrocyte sedimentation rate (ESR)
- C-reactive protein (CRP)
- Rheumatoid factor
- Antinuclear antibody (ANA)
- Anti-SSA/Ro and anti-SSB/La antibodies
- Complete blood count (CBC)
While some of these blood tests are more specific to Sjögren’s, such as anti-SSA/Ro and anti-SSB/La antibodies, having a combination of positive results can support a Sjögren’s diagnosis when considered along with a person’s reported symptoms and clinical examination by a doctor.
What is Sjögren’s syndrome?
Sjögren’s syndrome is a systemic autoimmune disease which means it affects the entire body. With Sjögren’s, the immune system mistakenly attacks the body’s own healthy cells and tissues. This leads to inflammation and damage to moisture-producing glands throughout the body, primarily:
- Lacrimal glands that produce tears for eye lubrication
- Salivary glands that produce saliva for mouth and throat lubrication
When these glands are damaged by the immune system, the main symptom is extreme dryness of the eyes and mouth. However, Sjögren’s syndrome can sometimes affect other moisture-producing glands in the body as well, leading to additional problems such as dry skin, vaginal dryness, respiratory symptoms, and more.
Primary vs Secondary Sjögren’s
There are two main classifications of Sjögren’s syndrome:
- Primary Sjögren’s syndrome – This refers to Sjögren’s occurring by itself, not in association with another autoimmune or rheumatic disease.
- Secondary Sjögren’s syndrome – This refers to Sjögren’s developing along with another autoimmune disease like rheumatoid arthritis, systemic lupus erythematosus (SLE), scleroderma, polymyositis, and others.
The symptoms and treatment tend to be similar regardless if it is primary or secondary Sjögren’s. However, people with primary Sjögren’s have a higher risk of developing lymphoma.
Common Symptoms of Sjögren’s Syndrome
Some of the most common symptoms of Sjögren’s syndrome include:
- Dry eyes – Irritation, itchiness, burning sensation, feeling like something is in the eye.
- Dry mouth – Decreased saliva leading to difficulty eating dry foods, swallowing, speaking, dental cavities.
- Joint pain – Can involve pain, stiffness, and swelling in joints.
- Fatigue – Feeling extremely tired physically and mentally.
- Digestive issues – Heartburn, reflux, abdominal pain.
- Dry skin – Itchy, scaly, cracked skin.
- Recurrent mouth sores – Painful sores or ulcers in the mouth.
- Difficulty swallowing – Food feeling stuck in throat.
- Dry cough – Persistent cough due to dry throat.
- Vaginal dryness – Discomfort especially during intercourse.
Some people with Sjögren’s syndrome also experience issues with their thyroid, liver, or kidneys. Lymphoma risk is also elevated.
Diagnosing Sjögren’s Syndrome
Diagnosing Sjögren’s can be difficult because symptoms are nonspecific and overlap with other conditions. There is no single test that confirms Sjögren’s. Instead, a combination of factors are used:
- Symptom history
- Clinical examination
- Physical tests of gland function
- Imaging tests
- Blood tests
- Biopsy of salivary glands
It may take time and multiple doctor visits to gather all the needed information to diagnose Sjögren’s syndrome. Keeping detailed symptom journals and being persistent with seeking care is key.
Blood Tests for Sjögren’s Syndrome Diagnosis
While no single blood test can definitively diagnose Sjögren’s syndrome, certain blood tests may provide useful information when considered along with a person’s full clinical presentation:
Complete Blood Count (CBC)
A CBC provides an overall picture of your blood health by measuring levels of various cells including red blood cells, white blood cells, and platelets. With Sjögren’s, CBC may show:
- Low red blood cell count (anemia)
- Low white blood cell count (leukopenia)
- High white blood cell count (leukocytosis)
- Low platelet count (thrombocytopenia)
These abnormalities in cell counts can indicate chronic inflammation and autoimmune activity occurring in the body.
Erythrocyte Sedimentation Rate (ESR)
The ESR blood test detects and monitors inflammation levels in the body. With Sjögren’s syndrome, the ESR result is often elevated due to high inflammation.
C-Reactive Protein (CRP)
CRP is another marker of systemic inflammation. Like ESR, CRP levels tend to be higher when chronic inflammation is present with Sjögren’s.
Rheumatoid Factor
Rheumatoid factor (RF) is an autoantibody that mistakenly attacks healthy tissue. About 60-70% of people with primary Sjögren’s will test positive for RF.
Antinuclear Antibody Test (ANA)
ANA detects autoantibodies targeting cell contents like DNA and histones. Approximately 70% of Sjögren’s patients test positive for ANA.
Anti-SSA and Anti-SSB Antibodies
- Anti-SSA antibodies (also called anti-Ro antibodies) are found in about 70% of people with primary Sjögren’s and 35% with secondary Sjögren’s.
- Anti-SSB antibodies (also called anti-La antibodies) are found in about 40% of people with primary Sjögren’s and 15% with secondary Sjögren’s.
Testing positive for anti-SSA and/or anti-SSB antibodies is one of the most specific blood test findings for Sjögren’s syndrome diagnosis.
IgG Levels
Immunoglobulin G (IgG) is an antibody blood levels of which may be elevated in Sjögren’s and other autoimmune disorders.
Beta-2 Microglobulin
Beta-2 microglobulin is a protein found on cell surfaces. Increased blood levels can indicate stimulation of the immune system and inflammation as seen with Sjögren’s.
Liver and Kidney Function Tests
Sjögren’s syndrome can sometimes affect organs like the liver and kidneys. Blood tests checking levels of liver enzymes, creatinine, and electrolytes may uncover dysfunction requiring treatment.
Interpreting Sjögren’s Blood Test Results
No single blood test can definitively diagnose Sjögren’s syndrome. However, certain patterns of test results can support a Sjögren’s diagnosis when considered along with a person’s reported symptoms and doctor’s clinical examination. Some findings that may support a Sjögren’s diagnosis include:
- Positive ANA and/or RF
- Positive anti-SSA and/or anti-SSB antibodies
- Elevated IgG levels
- Elevated inflammatory markers like CRP, ESR
- CBC abnormalities like cytopenias
People who test negative on Sjögren’s blood tests may still have the disorder. Repeat testing may be needed in some cases. Ultimately, the diagnosis is made based on the full clinical picture.
Sjögren’s Blood Tests Table Summary
| Blood Test | Potential Findings with Sjögren’s |
|---|---|
| Complete blood count (CBC) | Anemia, leukopenia, leukocytosis, thrombocytopenia |
| Erythrocyte sedimentation rate (ESR) | Elevated |
| C-reactive protein (CRP) | Elevated |
| Rheumatoid factor (RF) | Positive in 60-70% primary Sjögren’s |
| Antinuclear antibodies (ANA) | Positive in ~70% of Sjögren’s patients |
| Anti-SSA (Ro) antibodies | Positive in 70% primary, 35% secondary Sjögren’s |
| Anti-SSB (La) antibodies | Positive in 40% primary, 15% secondary Sjögren’s |
| Immunoglobulin G (IgG) | Often elevated |
| Beta-2 microglobulin | Elevated |
| Liver enzymes, electrolytes, creatinine | May indicate liver or kidney dysfunction |
Other Tests Used to Diagnose Sjögren’s
While blood tests provide one useful component in the Sjögren’s diagnostic process, doctors also gather information from:
Clinical History
The types of symptoms a person has been experiencing, their severity, timing, relieving and aggravating factors.
Physical Exam
Examining eyes, mouth, skin, joints for signs of dryness. Feeling for enlarged parotid salivary glands.
Testing Glandular Function
Examples include the Schirmer test for eye dryness and salivary gland function tests.
Imaging Tests
Imaging such as MRI or CT scans to look for structural abnormalities in glands.
Salivary Gland Biopsy
Removing a minor salivary gland for examination under a microscope for lymphocytic infiltration, considered the gold standard for diagnosis.
Doctors review the collective findings from the medical history, physical examination, imaging tests, lab work, and tissue biopsy to determine if a diagnosis of Sjögren’s syndrome is warranted.
Conclusion
In summary, there is no single blood test that can definitively diagnose Sjögren’s syndrome. However, certain blood test findings can provide supportive evidence for Sjögren’s when considered along with the patient’s clinical presentation and results of their physical examination, imaging, and other lab tests. Some of the most useful blood tests include ANA, rheumatoid factor, anti-SSA/Ro and anti-SSB/La antibodies, markers of inflammation like ESR and CRP, immunoglobulins like IgG, and CBC. While negative blood tests do not rule out Sjögren’s, having a combination of multiple positive antibody and inflammatory markers makes the diagnosis much more likely when coupled with a patient’s characteristic symptoms of dry eyes, dry mouth, joint pain and autoimmune profile.
