The sensitivity of a synovial fluid analysis for crystals is 84%, with a specificity of 100%. If gout remains a clinical consideration after negative analysis findings, the procedure can be repeated in another joint or with a subsequent flare Crystals may be absent very early in a flare. t. Strongly negative birefringent双折 射的, needle-shaped crystals diagnostic gout obtained from an acutely inflamed oint Gout. Needles of urate on polarizing microscopy偏光显微术 浙医二院13 浙医二院 Gout. Needles of urate on polarizing microscopy偏光显微术 Gout. Strongly negative birefringent双折 射的, needle-shaped crystals diagnostic of gout obtained from an acutely inflamed joint The sensitivity of a synovial fluid analysis for crystals is 84%, with a specificity of 100%.If gout remains a clinical consideration after negative analysis findings, the procedure can be repeated in another joint or with a subsequent flare. Crystals may be absent very early in a flare