1. A method for checking a blood condition, comprising: supplying blood to a centrifugal container of a disk; centrifuging the blood in the centrifugal container to isolate blood cells and plasma by rotating the disk and detecting an actual moving distance of the blood cells in the centrifugal container every hour; and calculating a first curve representing the actual moving distance of the blood cells in the centrifugal container every hour and a second curve representing a theoretical moving distance of the blood cells every hour, and calculating hematocrit of the blood and viscosity of the plasma by comparing the first curve and the second curve.