Why testing is critical to early diagnosis of rheumatoid arthritis

Why optimal assays and the right tools make a difference in rheumatoid arthritis diagnosis

Presented by Derrick Varner, PhD, PA-C, DFAAPA, RDMS and Crista C. Prates, DNP, APRN-C

Diagnosing rheumatoid arthritis (RA) can have its challenges, including a risk of misdiagnosis. Early diagnosis is crucial for improved patient outcomes, and combining assays can lead to increased diagnostic confidence. Watch our continuing education webinar (click on the graphic below) from Lab Week 2025 to better understand how optimal assays and tools can make all the difference in diagnosing and managing RA. 

Increasing rheumatoid arthritis diagnostic confidence

Rheumatoid arthritis (RA) is an incurable autoimmune disease and can have debilitating effects. This autoimmune disease targets synovial tissues in our joints, and in addition to pain, inflammation, and permanent cartilage damage, RA is linked to numerous other comorbidities including heart disease, infections, and even cancer.¹

Like other autoimmune diseases, RA can be difficult to diagnose because its symptoms are generalized and may overlap with other inflammatory diseases.² As you'll see in our 2025 Lab Week webinar, serological testing can make all the difference in getting to a diagnosis faster. Labs that combine key assays can better support clinicians and patients in diagnosing — and therefore treating — this debilitating disease.

The risks of delay in diagnosing rheumatoid arthritis

RA affects approximately 18 million people worldwide, and about 70% of those patients are women.¹ Diagnosing rheumatoid arthritis can be challenging because the symptoms mimic many other conditions, and clinicians who aren’t specialists in identifying autoimmune diseases may not spot the signs early. In fact, it takes an average of 4.6 years to get to a diagnosis of an autoimmune disease.²

But RA patients are in a race against time — permanent joint damage can take place in just three months after the onset of symptoms.³ The first few months after symptoms appear are considered a “window of opportunity” to slow disease progression with early intervention and treatment.³ This means it’s crucial to get to a diagnosis of RA as soon as possible.

RA also involves many comorbidities that can endanger patients’ health over time. For example, RA patients are 33% more likely to have cardiovascular disease, and they’re at increased risk of heart failure.⁴ They have a higher risk of infection, and these patients can even have a greater risk of developing lymphoma, more than double the risk of the non-RA population.⁴

All of these risk factors make it important that patients receive a diagnosis quickly so they can begin symptom management — and that’s where laboratorians and serological testing come in. 

How combined testing assays can beat the clock

As highlighted in the webinar, in 2010, the American College of Rheumatology (ACR) and the European League against Rheumatism (EULAR) released new classification criteria for RA with two of the four classification domains involving blood tests.⁵ The key blood-based markers are rheumatoid factor (RF) and anticyclic citrullinated peptide (anti-CCP).⁶ 

Testing for RF and anti-CCP is crucial because RF is a very common marker for RA, but anti-CCP is more specific.⁶ Combining tests for the two therefore increases the chances of making an accurate diagnosis. Measuring multiple isotypes – like IgA, IgM, and IgG – increases the chances of making a serological RA diagnosis.⁷ Researchers have found that testing for these RF isotypes and anti-CCP results in specificity of nearly 100%.⁷

By combining these serological tests, labs can cut through the uncertainty around RA and help clinicians get to a diagnosis faster. Why is this so important? Because medications and interventions can slow the progression of RA. Disease-modifying anti-rheumatic drugs or steroids can help ease inflammation, and rehabilitative strategies like exercise are an important part of symptom management.¹ But all of these interventions follow an accurate diagnosis, which means labs must be ready to provide the most comprehensive testing for better patient care.

Phadia™ Laboratory Systems can run RF-IgA, RF-IgM and anti-CCP EliA™ assays in parallel, which improves diagnostic confidence without complicating a lab’s workflow. Providing the most comprehensive recommended testing means better support for clinicians trying to sift through RA symptoms, especially primary care physicians who may not be as familiar with autoimmune condition symptoms as rheumatologists are. 

And, at the end of the day, these testing processes can help get patients to a faster diagnosis and thus earlier intervention in RA to improve their quality of life.