Joint aspiration (Chapter 124)

X-ray joint for baseline

Blood glucose

Creatinine and electrolytes

Liver function tests

Full blood count

Erythrocyte sedimentation rate and C-reactive protein

Blood culture (×2)

Urine stick test, microscopy and culture

Swab of urethra, cervix and anorectum for culture and nucleic acid amplification test (NAAT) if gonococcal infection is possible