A Comprehensive Approach to Differential Diagnosis
“Arthritis” encompasses more than 100 distinct conditions. Because symptoms such as joint pain, stiffness, and swelling often overlap, distinguishing between inflammatory and non-inflammatory forms is essential for appropriate treatment planning.
DLO offers a broad menu of laboratory testing to support efficient differential diagnosis and earlier therapeutic decision-making.
Osteoarthritis (OA): Clarifying a Common Diagnosis
Often referred to as “wear-and-tear” arthritis, osteoarthritis is the most prevalent form, affecting more than 30 million Americans.
OA and rheumatoid arthritis (RA) can present with similar clinical features, including:
- Joint pain and stiffness
- Swelling
- Reduced range of motion
However, treatment strategies differ significantly, making accurate differentiation critical.
Diagnostic evaluation may include:
- Clinical presentation and joint involvement
- Patient age and symptom pattern
- Radiologic findings (e.g., osteophytes, joint space narrowing)
- Synovial fluid analysis (appearance, WBC count)
- Inflammatory markers such as erythrocyte sedimentation rate (ESR)
Unlike RA, OA typically does not present with elevated autoimmune markers. Laboratory testing plays an important role in ruling out inflammatory arthritis.
Osteoarthritis tests:
Rheumatoid Arthritis (RA): Early Detection Matters
Rheumatoid arthritis is a systemic autoimmune disease that affects approximately 165,000 newly diagnosed patients each year in the United States. It most commonly presents with symmetrical involvement of small joints—particularly fingers and wrists—and occurs more frequently in women.
Because RA can lead to progressive joint damage and may involve extra-articular systems such as the heart and lungs, early identification is essential.
DLO supports RA evaluation with testing that may include:
- Rheumatoid factor (RF)
- Cyclic citrullinated peptide (CCP) antibody
- C-reactive protein (CRP)
- Erythrocyte sedimentation rate (ESR)
Elevated RF or CCP antibodies may suggest inflammatory arthritis and help distinguish RA from OA.
Rheumatoid arthritis tests:
- Cyclic Citrullinated Peptide (CCP) Antibody
- Rheumatoid Arthritis Diagnostic Panel 2
- Rheumatoid Factor
- C-Reactive Protein (CRP)
- Mutated Citrullinated Vimentin (MCV) Antibody
- 14-3-3 eta Protein
- Erythrocyte Sedimentation Rate (ESR or sed rate)
- ANA, IFA, Cascade and Rheumatoid Arthritis Panel 2, Reflexes
- Pre-biologic/biosimilar Screen Panel, HCV/HBV with Reflexes and QFT 1 tube*
-
Pre-biologic/biosimilar Screen Panel, HCV/HBV with Reflexes and QFT 4 tubes*
*Panel components may be ordered separately.
Psoriatic Arthritis (PsA): Identifying Inflammatory Joint Disease
Psoriatic arthritis develops in approximately 10–20% of patients with psoriasis. While it may share characteristics with RA, PsA can involve joints, ligaments, and tendons and may require a distinct management strategy.
Clinical assessment typically includes patient history, family history, and physical examination. Laboratory testing may assist by:
- Ruling out RA (RF and CCP antibody)
- Documenting inflammation (CRP and/or ESR)
- Evaluating for anemia (hemoglobin or complete blood count)
DLO’s expanding test menu supports clinicians in evaluating suspected PsA and other inflammatory arthritides.
Psoriatic arthritis tests:
Partner with DLO for Arthritis Testing Support
From first-line evaluation to ongoing monitoring, DLO provides:
- Broad access to autoimmune and inflammatory testing
- Reliable turnaround times
- Consultative support
- Integration with your clinical workflow
When arthritis is part of the differential, you can rely on DLO to help guide clinical insight and support timely patient care.
Visit the Quest Diagnostics Test Directory
View Lab and Database Updates through IntelliTest Manager™
