Published: May 2026
At the 15th International Congress on Autoimmunity, Thermo Fisher Scientific hosted a series of Ask the Expert sessions focused on practical challenges in autoimmune diagnostics with leading clinical and laboratory experts.
Across discussions with Professor Ricard Cervera, Dr. Lieve van Hoovels and Dr. Jan Damoiseaux, one recurring theme emerged: improving autoimmune diagnostics is not about doing more testing by default. It is about recognizing complexity earlier, interpreting results more meaningfully and using testing strategies that align with the clinical question.
Recognize complexity: autoimmune diseases often do not come alone
In the session on polyautoimmunity, Professor Ricard Cervera (Hospital Clínic de Barcelona, Barcelona, Spain) emphasized that many patients with autoimmune disease present with more than one autoimmune condition over time.
“Polyautoimmunity is the norm, but not only nowadays. It has probably always been the norm.”
He noted that maybe 80–90% of patients with autoimmune diseases may present with a combination of more than one autoimmune disease. In his view, this is not necessarily a new phenomenon, but a clinical reality that is now better recognized through greater awareness and education.
Professor Cervera also stressed that autoimmune diseases often begin with mild or nonspecific symptoms, abnormal laboratory findings or manifestations affecting different organ systems. Some patients show features of several autoimmune diseases but do not yet fulfill established criteria. This is one reason diagnosis can take time.
A key point was the distinction between classification and diagnosis. Classification criteria are important for research, clinical trials and registries, but they do not always reflect the complexity of real clinical practice. Because diagnostic guidelines are limited for many autoimmune diseases, classification criteria can support assessment, but clinical diagnosis remains central to patient care.
In practice, the first autoimmune diagnosis may not always represent the full clinical picture. For example, in patients with systemic lupus erythematosus, diagnostic and management strategies should also include ruling out commonly associated conditions such as antiphospholipid syndrome, Sjögren’s syndrome or autoimmune thyroiditis.
For testing, Professor Cervera argued for balance:
- Not ordering hundreds of tests without direction
- Not relying only on a single marker such as antinuclear antibodies
- Using structured algorithms to guide next diagnostic steps
The session also reinforced the importance of integrated care and clear communication. As primary care often represents the first stage of the patient journey, collaboration between laboratories, referral centers and specialists is critical. Providing clinical context with laboratory requests and maintaining communication between everyone involved in autoimmune care can help reduce diagnostic delays.
Interpret results meaningfully: beyond positive or negative
Dr. Lieve van Hoovels (AZORG Hospital, Aalst, Belgium) focused on likelihood ratios and how they can improve interpretation of autoimmune test results.
She explained that different commercial assays may measure the same antigen or antibody but still differ in methodology, calibration, reagents and reporting units. As a result, values from different assays are not always directly comparable and a simple positive or negative interpretation may not provide enough clinical context.
“Likelihood ratios provide clinically relevant interpretation that is much more useful than a dichotomous positive or negative interpretation based only on a cutoff.”
Likelihood ratios help indicate how strongly a test result is associated with the likelihood of disease. They can also support more harmonized interpretation across methods, especially when thresholds are based on predefined specificity levels rather than manufacturer cutoffs alone.
The practical implication is clear:
- Clinicians and laboratories need reporting approaches that help translate test results into clinical meaning
- Interpretation becomes especially important when assay methods differ across platforms
- Consistency matters when patients move between healthcare centers or laboratories
Implementation still requires education and collaboration. Dr. van Hoovels stressed that clinicians need to understand inter-assay variability and the added value of likelihood ratios. Laboratory specialists can support adoption through:
- Results interpretation guides
- Clinical case discussions
- Multidisciplinary exchange
- Training on assay variability and likelihood ratio interpretation
Test with purpose: avoid both missed diagnoses and false-positive follow-up pathways
Dr. Jan Damoiseaux (Maastricht University Medical Center, Maastricht, The Netherlands) addressed diagnostic stewardship in autoimmunity: how to choose the right test for the right patient and how to interpret the test result in context.
He described diagnostic stewardship as supporting clinicians in selecting the most appropriate tests based on the clinical situation and then helping interpret the results, including weak or strong positives.
“It’s not just saying, ‘Which kind of test should be done in this case?’ but also, ‘How do we interpret weak positive results or strong positive results?’”
The discussion highlighted the tension between early detection and the risk of false positive test results. Early diagnosis matters because delayed treatment can mean missed opportunities to prevent tissue damage. But broad screening in low-risk populations can create anxiety, unnecessary follow-up and misdirected care.
One of the strongest messages from the session was the potential harm of false positive results. If a false positive result leads clinicians toward the wrong diagnostic pathway, it may delay the correct diagnosis and the treatment the patient actually needs.
For Dr. Damoiseaux, the foundation of better test utilization is communication.
“There is one key word: communication.”
In practice, this means:
- Closer collaboration between clinicians and laboratories
- Clearer diagnostic algorithms for appropriate autoimmune test selection
- Digital test-ordering guidance based on the clinical question
- Multidisciplinary case discussions for complex or unclear results
- Education for clinicians who request autoimmune testing
What this means in practice
Taken together, the three sessions point toward a practical model for more effective autoimmune diagnostics:
- Look beyond the first autoimmune diagnosis. Patients may develop multiple autoimmune diseases over time.
- Use structured diagnostic algorithms instead of relying only on isolated markers or broad untargeted panels.
- Include relevant clinical information with laboratory requests to support meaningful interpretation.
- Move beyond simple positive or negative reporting when more clinically useful interpretation with likelihood ratios is available.
- Consider pre-test probability before testing, especially to reduce false-positive follow-up pathways.
- Strengthen communication between primary care, specialists and diagnostic laboratories.
Take-home message
Autoimmune diagnostics are becoming more complex, but the answer is not simply more testing. A stronger path forward is more purposeful testing:
- Recognizing overlapping autoimmune diseases
- Interpreting results in clinically meaningful ways by e.g. using likelihood ratios
- Applying diagnostic stewardship to help ensure testing is appropriate, efficient and useful for patient care
Learn more
To learn more about how these principles apply in practice, explore our EliA™ test algorithms designed to support smarter autoimmune diagnostics.
Medical disclaimer: This article may contain general information relating to medical conditions and their treatment. The information is provided for informational purposes only and is not a substitute for professional medical advice. Always consult a qualified health care professional for diagnosis and treatment decisions.
Third-party disclaimer: Thermo Fisher Scientific does not endorse or recommend any specific clinical practices presented by external experts.
