Abstract: A blood-viscosity measurement blood collection tube includes a bottomed tube provided with an opening at one end in a length direction and a bottom at the other in the length direction, and a sealing plug. The sealing plug includes a sealing part fitted in the opening of the bottomed tube in a hermetically sealed state, a cap part, and a thin connecting part. The sealing part includes a vertically penetrated insertion hole. The sealing part of the sealing plug is fitted in the opening of the bottomed tube, and an inner space of the bottomed tube is in a negative pressure state. The cap part is configured to be removed from the sealing plug by breaking the connecting part with an external force applied to the cap part, and the insertion hole is exposed at an upper surface of the sealing part when the cap part has been removed.

Abstract: A blood-viscosity measurement method uses a collection tube includes a bottomed tube having an opening at one end in a length direction and a bottom at the other end in the length direction. A sealing plug includes a sealing part fitted in the opening of the bottomed tube in a hermetically sealed state, a cap part, and a thin connecting part. The sealing part includes a vertically penetrated insertion hole and fitted in the opening of the bottomed tube. The method includes collecting blood using a negative pressure state of the inner space, applying an external force to the cap portion to break the connecting part and removing the cap part to expose the insertion hole at an upper surface of the sealing part, and obtaining blood viscosity by causing a viscosity-measurement falling body to fall from the insertion hole, and measuring a fall terminal velocity of the falling body.