Initial Laboratory Tests and Treatment Options for Suspected Rheumatic Diseases

Initial Laboratory Evaluation

The American College of Rheumatology recommends a complete autoantibody panel, inflammatory markers, complete blood count, and renal function assessment for patients with suspected rheumatic disease, with a strength of evidence of high 1
Renal function tests, including serum creatinine, should be performed to assess for renal involvement in patients with suspected rheumatic disease, with a strength of evidence of moderate 1, 2
Urinalysis and urine protein/creatinine ratio should be performed to assess for renal involvement in patients with suspected rheumatic disease, with a strength of evidence of moderate 1, 2
Liver function tests should be performed to establish a baseline before treatment in patients with suspected rheumatic disease, with a strength of evidence of low 3

Antinuclear antibody (ANA) should be used as a screening test for systemic autoimmune diseases in patients with suspected rheumatic disease, with a strength of evidence of high 2
Rheumatoid factor (RF) and anti-cyclic citrullinated peptide (anti-CCP) antibodies should be tested for suspected rheumatoid arthritis, with a strength of evidence of moderate 4
For suspected systemic lupus erythematosus (SLE), anti-dsDNA, anti-Ro/SSA, anti-La/SSB, anti-RNP, and anti-Sm antibodies should be tested, with a strength of evidence of moderate 2

Methotrexate is typically the first-line disease-modifying antirheumatic drug (DMARD) for rheumatoid arthritis, with a strength of evidence of high 3
For mild symptoms with inflammation, acetaminophen and/or NSAIDs should be used, with a strength of evidence of low 4, 5
For moderate to severe disease, combination therapy with conventional synthetic DMARDs and biologic agents should be considered, with a strength of evidence of moderate 3, 5
Glucocorticoids at low doses for short durations can be used as bridge therapy, with a strength of evidence of low 3, 5

Laboratory monitoring intervals for patients on DMARDs should be every 2-4 weeks for the first 3 months, then every 8-12 weeks, with a strength of evidence of moderate 3
More frequent monitoring should be performed for patients with comorbidities or abnormal laboratory results, with a strength of evidence of low 3, 1

Plain X-rays should be considered to evaluate joint damage (erosions) in suspected inflammatory arthritis, with a strength of evidence of low 4, 5
Ultrasound or MRI should be performed for persistent arthritis unresponsive to treatment, with a strength of evidence of low 4, 5
Arthrocentesis should be considered if septic arthritis or crystal-induced arthritis is suspected, with a strength of evidence of low 4, 5
Early referral to a rheumatologist is recommended for patients with joint swelling (synovitis) or persistent symptoms, with a strength of evidence of moderate 4, 5
Rheumatologist consultation is essential for complex cases or when initiating biologic therapy, with a strength of evidence of moderate 3, 5
Failing to screen for infections before starting immunosuppressive therapy should be avoided, with a strength of evidence of high 3, 1