Learn About Sjögren Syndrome Testing Methods

Understanding Sjögren Syndrome and Why Testing Matters

Sjögren syndrome is a long-term autoimmune disease that primarily affects the glands responsible for producing moisture in the body. In this condition, the immune system mistakenly attacks the lacrimal glands (which produce tears) and the salivary glands (which produce saliva). This leads to the two main symptoms most people experience: dry eyes and dry mouth. However, Sjögren syndrome can also affect other parts of the body, including joints, nerves, kidneys, and the lungs.

The disease was first described in detail by Swedish ophthalmologist Henrik Sjögren in 1933, though cases of severe dry mouth and dry eyes had been documented long before. Today, an estimated 0.5 to 1 million people in the United States live with Sjögren syndrome, though many cases remain undiagnosed for years.

Testing for Sjögren syndrome matters because early detection can lead to better management of symptoms and prevention of complications. Without diagnosis, people often suffer with unexplained dryness and may develop secondary infections or tissue damage. Additionally, because Sjögren syndrome can affect multiple organ systems, diagnosis helps doctors understand whether other health problems a person experiences might be connected to this condition rather than being separate issues.

The condition comes in two forms. Primary Sjögren syndrome occurs on its own, while secondary Sjögren syndrome develops alongside another autoimmune disease, most commonly rheumatoid arthritis or lupus. Understanding which type a person has influences how doctors approach treatment and monitoring.

Practical Takeaway: If you have experienced persistent dry eyes and dry mouth lasting more than three months, along with other symptoms like joint pain or fatigue, learning about testing methods can help you understand what doctors might look for and why various tests are performed.

Blood Tests and Antibody Screening

Blood tests form the foundation of Sjögren syndrome testing because they can detect specific antibodies and proteins that appear when the immune system is attacking the body's own tissues. These blood markers are crucial diagnostic clues that help doctors confirm whether someone has Sjögren syndrome or whether their symptoms stem from another cause.

The most important antibodies tested for in Sjögren syndrome are anti-SSA (also called anti-Ro) and anti-SSB (also called anti-La). SSA stands for "Sjögren syndrome antigen A" and SSB stands for "Sjögren syndrome antigen B." These are protein components that the immune system produces antibodies against in this disease. Research shows that approximately 40 to 60 percent of people with primary Sjögren syndrome test positive for anti-SSA antibodies, and about 40 to 50 percent test positive for anti-SSB antibodies. When someone tests positive for anti-SSB, they almost always also test positive for anti-SSA.

Another important blood test measures rheumatoid factor (RF), which appears in about 50 to 60 percent of Sjögren syndrome cases. Antinuclear antibody (ANA) testing is also performed, with positive results occurring in 50 to 80 percent of cases. These tests show that the immune system is producing antibodies, though they are not specific to Sjögren syndrome alone.

Doctors also measure immunoglobulin levels, particularly IgM and IgG, which may be elevated in people with Sjögren syndrome. Complement levels (particularly C3 and C4) may be low. Additionally, blood tests can measure erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP), which indicate inflammation in the body.

A complete blood count (CBC) may show anemia or low white blood cell counts, which can occur in Sjögren syndrome. Liver and kidney function tests are also performed since this disease can affect these organs. Thyroid function tests are included because people with Sjögren syndrome have increased risk of thyroid disease.

Practical Takeaway: Blood tests cannot diagnose Sjögren syndrome by themselves, but they provide important information about what is happening in your immune system. Understanding what these antibodies and proteins mean helps you discuss results with your healthcare provider and understand why additional testing may be necessary.

Tear and Saliva Production Tests

Since Sjögren syndrome directly damages the glands that produce tears and saliva, testing the actual production of these fluids provides objective evidence of gland damage. These tests measure whether the eyes and mouth are producing normal amounts of moisture, which is essential for comfort and health.

The Schirmer test is one of the oldest and most commonly used tests for measuring tear production. In this test, a thin strip of filter paper is placed on the inner lower eyelid and left there for five minutes without touching the eye surface. The length of paper that becomes wet with tears is then measured. A normal result shows that at least 15 millimeters of the paper became wet in five minutes. A result of 5 millimeters or less suggests insufficient tear production. Results between 5 and 15 millimeters fall in a gray area and may need to be interpreted along with other test results. Studies show that the Schirmer test has a sensitivity of about 40 to 50 percent for Sjögren syndrome, meaning it catches about half of actual cases.

There is also a variant called the anesthetic Schirmer test, where anesthetic drops are placed on the eye first. This prevents the eye from producing reflex tears in response to the irritation of the paper strip, making it measure only the basic tear production that occurs naturally. This version may be more specific for identifying true dry eye from Sjögren syndrome rather than dry eye from other causes.

The ocular staining test looks for damage to the surface of the eye caused by dryness. Doctors use special dyes—typically fluorescein or lissamine green—to stain the eye. Areas where cells have died from dryness will take up the dye and become visible. The Van Bijsterveld score rates the staining pattern on a scale of 0 to 9, with higher numbers indicating more damage.

For measuring saliva production, doctors use the unstimulated whole saliva test. A person sits quietly for five minutes while saliva drips into a collection cup without any stimulation to produce saliva. Normal unstimulated saliva flow is greater than 1.5 milliliters over five minutes. Less than 0.1 milliliters over five minutes indicates severely reduced saliva production. The stimulated saliva test involves chewing on a piece of gum or paraffin wax for one minute while saliva is collected. Normal stimulated flow is greater than 5 milliliters over five minutes.

Practical Takeaway: These functional tests show whether your eyes and mouth are actually dry in measurable ways. They help distinguish between Sjögren syndrome and other causes of dry eyes or mouth, and they provide a baseline against which future changes can be measured.

Imaging and Biopsy Tests

While blood tests show immune system activity and functional tests measure moisture production, imaging and biopsy tests provide direct visual or microscopic evidence of gland damage. These tests can definitively show that the salivary glands have been damaged by the immune system attacking them.

Salivary gland scintigraphy uses radioactive tracer material to visualize how well the salivary glands are functioning. A small amount of radioactive material is injected, and it concentrates in the salivary glands. A special camera then takes images showing whether the glands are taking up the material normally. In Sjögren syndrome, the glands show delayed uptake of the tracer and delayed release of saliva. This test is sensitive and specific for Sjögren syndrome, with studies showing about 90 percent accuracy.

Ultrasound imaging of the salivary glands has become increasingly popular because it requires no radiation and is less costly than scintigraphy. Ultrasound can show changes in the internal structure of the salivary glands, including the formation of small cystic spaces and areas of fibrosis (scarring). The glands may appear bright with scattered dark spots, described as a "snow storm" or "honeycomb" appearance. High-resolution ultrasound has shown promise in detecting these changes with good sensitivity and specificity.

Magnetic resonance imaging (MRI) can also visualize the