Abstract: Tube and cap assemblies for retaining an aliquot of fluid suitably for transferring such samples within a laboratory or between laboratories include a tube portion having at least one sidewall defining an open top. A flange extends outwardly from the open top and includes a top surface and a bottom surface. At least one channel is provided in the top surface of the flange, and an internal closed bottom extends from the at least one sidewall. The cap includes at least one peripheral wall, a hub inset from the at least one peripheral wall, and a plurality of ribs extending from the hub to the at least one peripheral wall to strengthen it against forces inward toward the hub. The cap further includes a neck having at least one bubble ring, a rim extending from the neck, and at least one sealing rib extending from the rim.

Abstract: Tube and cap assemblies for retaining an aliquot of fluid suitably for transferring such samples within a laboratory or between laboratories include a tube portion having at least one sidewall defining an open top. A flange extends outwardly from the open top and includes a top surface and a bottom surface. At least one channel is provided in the top surface of the flange, and an internal closed bottom extends from the at least one sidewall. The cap includes at least one peripheral wall, a hub inset from the at least one peripheral wall, and a plurality of ribs extending from the hub to the at least one peripheral wall to strengthen it against forces inward toward the hub. The cap further includes a neck having at least one bubble ring, a rim extending from the neck, and at least one sealing rib extending from the rim.