Laboratory Testing for Inflammation

Essential First-Line Inflammatory Markers

The American College of Rheumatology recommends ordering C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) as initial inflammatory markers for patients presenting with inflammatory symptoms, with CRP being the preferred test due to its reliability and rapid response to changes in disease activity 1, 2
CRP is superior to ESR for monitoring inflammation because it is not influenced by age, gender, or anemia, and provides a simple, validated, reproducible result 1, 2

The American College of Rheumatology suggests ordering antinuclear antibodies (ANA) if the diagnosis remains uncertain after initial workup or if symptoms suggest systemic lupus erythematosus or other connective tissue diseases, with a strength of evidence of moderate to high 3, 4, 1, 2
ANA serves as a screening test but should not delay rheumatology referral if clinical synovitis is present, with a sensitivity of 70-90% and specificity of 90-95% 1, 5

The American College of Rheumatology recommends obtaining bilateral hand, wrist, and foot X-rays at baseline to assess for erosions, which predict rheumatoid arthritis diagnosis and disease persistence, with a strength of evidence of high 2
Ultrasound with Power Doppler is superior to clinical examination for detecting subclinical synovitis and can detect inflammation that predicts disease progression even when physical examination is normal, with a sensitivity of 80-90% and specificity of 90-95% 2

The American College of Rheumatology recommends repeating CRP and ESR every 4-6 weeks after starting treatment to monitor disease activity and treatment response, with a strength of evidence of moderate to high 3, 4, 1
Serial inflammatory markers guide treatment escalation but should not be the sole determinant of treatment decisions, with a strength of evidence of moderate 1

The National Comprehensive Cancer Network recommends continuing any ongoing cancer therapy if this is immune checkpoint inhibitor-related, and initiating acetaminophen and/or NSAIDs for symptom control, with a strength of evidence of high 6, 3, 4
The American College of Rheumatology suggests escalating to higher-dose NSAIDs if inadequately controlled with initial therapy, and initiating prednisone 10-20 mg/day if NSAIDs are insufficient, with a strength of evidence of moderate to high 6, 3, 4
The American College of Rheumatology recommends considering disease-modifying antirheumatic drugs (DMARDs) if no improvement after 4 weeks or if unable to taper corticosteroids below 10 mg/day after 3 months, with a strength of evidence of high 6, 3, 4