Diagnosis is more than one blood result
Gout is diagnosed from the overall clinical picture. Serum urate is useful, but a single number cannot confirm or exclude gout on its own.
Joint aspiration can provide stronger confirmation
When the diagnosis is uncertain, fluid can be taken from a joint and examined for monosodium urate crystals.
Timing matters
Serum urate can be lower during an acute flare. If gout is still suspected after a lower reading during a flare, repeat testing after symptoms settle may be useful.