Crystallization of the K-CITR buffer may occur, this is not unusual for concentrated solutions stored at 4°C.
This will not affect the integrity of the kit, but needs to be redissolved to ensure the correct concentration of the buffer for the assay. Leaving the buffer at room temperature for approximately 30 mins before making up the solution should result in a significant reduction of the crystals formed. Alternatively heat the buffer gently to ~ 40C with intermittent mixing to dissolve all crystals prior to use.