• X-ray of involved joints
• Aspiration of involved joint (samples for crystal analysis, microscopy and culture)
• Blood culture (×2) if febrile
• Creatinine and electrolytes
• Urate level (may be normal in acute gout; gout and pseudogout may coexist)
• Full blood count

If pseudogout confirmed:

• Bone profile: calcium and phosphate, alkaline phosphatase
• Magnesium
• Ferritin, serum iron and total iron binding capacity (to assess for haemochromatosis)
• Thyroid stimulating hormone (hypothyroidism and pseudogout often coexist)
• Parathyroid hormone levels (if hypercalcaemia)