Gout Diagnosis: Clinical Criteria, Lab Tests & Imaging

Gout diagnosis combines clinical, laboratory, and imaging findings:

1. History & Exam: Acute monoarthritis (often 1st MTP), severe pain, erythema, swelling; prior flares
2. Serum Urate: >6.8 mg/dL supports but not diagnostic; normal during acute flare possible
3. Synovial Fluid Analysis (Gold Standard): Needle-shaped, negatively birefringent monosodium urate crystals under polarized light
4. Imaging: X-ray (late: punched-out erosions, overhanging edges), US (double contour sign, tophi), DECT (urate-specific color mapping)

ACR/EULAR 2015 Classification Criteria

Entry: ≥1 episode of swelling/pain/tenderness in a joint/bursa. Then score-based: clinical, lab, imaging features. ≥8 points = gout.

Early diagnosis prevents joint destruction and comorbidity progression.