1977 ACR classification criteria for acute gouty arthritis 1. Specific urate crystals in the joint fluid, 2. Chemical or polarized light microscopy to confirm the presence of urate crystals in the gouty stone, 3. 6 of the following 12 items (clinical, laboratory, and x-ray manifestations) are present, 1) >1 episode of acute arthritis. (2) Inflammatory response peaks within 1 day. (3) Episodes of monoarthritis. (4) Redness of the joint is visible. (5) Pain or swelling of the first metatarsophalangeal joint. (6) Unilateral involvement of the first metatarsophalangeal joint. (7) Unilateral tarsal joint involvement. (8) Suspected gout stone. (9) Hyperuricemia. (10) Asymmetric intra-articular swelling (confirmed by X-ray). (11) Subcortical cysts without bone erosion (confirmed by X-ray). (12) Negative microbiological culture of joint fluid at the onset of arthritis.