Capillary transfer pipettes and related methods

A method of collecting liquid with a capillary transfer pipette having a draw tube, a volume indicating element provided directly on the draw tube during formation of the capillary transfer pipette, wherein the volume indicating element comprises a radially outwardly projecting annular rib defined by a discrete rounded expansion of the draw tube, an air vent hole extending through the volume indicating element and being provided during formation of the capillary transfer pipette, and at least one fin extending longitudinally and having a distal end, wherein the distal end of the at least one fin is arranged so as to not extend distally beyond the air vent hole, the method comprising:

• positioning a distal opening of the draw tube in contact with a liquid to be drawn via capillary action;
• drawing the liquid into the draw tube via capillary action;
• and
• selectively obstructing the air vent hole when a proximal surface of the drawn liquid reaches the volume indicating element so as to cease drawing of the liquid into the draw tube.

A method of making a capillary transfer pipette, the method comprising:

• extruding a parison of molten polymeric material;
• positioning the parison within a mold cavity defined between first and second mold structures and having a cavity wall;
• injecting air into the parison so that the parison expands within the mold cavity and conforms to the cavity wall to form a capillary transfer pipette, the mold cavity being shaped so as to provide the capillary transfer pipette with a draw tube having a lumen and configured to draw liquid via capillary action, a volume indicating element provided directly on the draw tube in response to the air being injected into the parison, the volume indicating element comprising an outwardly projecting annular rib defined by a discrete rounded expansion of the lumen, a squeeze bulb arranged proximally of the draw tube and configured to be compressed to dispense drawn liquid from the draw tube, and at least one fin extending longitudinally and having a distal end;
• and
• forming an open air vent hole in the volume indicating element during formation of the capillary transfer pipette, the air vent hole being configured to vent air therethrough to facilitate drawing of liquid by the draw tube via capillary action,
• wherein the distal end of the at least one fin is arranged so as to not extend distally beyond the air vent hole.