Which of the following is the best investigation for acute gout?

in Acute gout there is increase in value of uric acid but when acute gout attack sta, uric acid is not elevated in blood, but elevated in synol fluid. Acute gout- uric acid in synol fluid. Chronic Gout - S. Uric acid. Acute gout condition has crystallization of uric acid in the joint space IOC - uric acid in synol fluid (Joint Aspiration) These crystals exhibiting -vet birefringence in polarized light.