A method of preparing reagents, the method comprising: inserting a cartridge (102, 202, 804, 1900) into an instrument (100, 200), the cartridge (102, 202, 804, 1900) including a plurality of flexible reagent enclosures (214, 1110, 1610, 2128), disposed in a cavity of the cartridge (102, 202, 804, 1900), and each reagent enclosure (214, 1110, 1610, 2128) exposing an opening to an exterior of the cartridge (102, 202, 804, 1900) to provide fluid access to the interior of each reagent enclosure (214, 1110, 1610, 2128), each reagent enclosure (214, 1110, 1610, 2128) including a reagent container (1120, 1620) including a reagent and an internal cavity (1320, 1820) defining a compressible volume, a passage (1230, 1330, 1510) defined through the reagent container (1120, 1620) to the internal cavity (1320, 1820); connecting a plurality of fluid ports (810, 1906, 1908, 1910, 1912, 1914) to the openings of the plurality of reagent enclosures (1110, 1610, 2128); applying a solution through the fluid ports (810, 1906, 1908, 1910, 1912, 1914) to at least partially fill the plurality of reagent enclosures (214, 1110, 1610, 2128); cycling a pressure of the cavity through a gas port fluidically communicating the cavity with an exterior of the cartridge (102, 202, 804, 1900), whereby for each of the reagent enclosures (214, 1110, 1610, 2128), during increasing pressure, the solution enters the internal cavity (1320, 1820) of the reagent container (1120, 1620), combines with the reagent, and compresses the compressible volume, and during decreasing pressure, the compressible volume decreases and the reagent is ejected through the passage (1230, 1330, 1510), and reading an identification tag of the cartridge (102, 202, 804, 1900) with the instrument (100, 200). inserting a cartridge (102, 202, 804, 1900) into an instrument (100, 200), the cartridge (102, 202, 804, 1900) including a plurality of flexible reagent enclosures (214, 1110, 1610, 2128), disposed in a cavity of the cartridge (102, 202, 804, 1900), and each reagent enclosure (214, 1110, 1610, 2128) exposing an opening to an exterior of the cartridge (102, 202, 804, 1900) to provide fluid access to the interior of each reagent enclosure (214, 1110, 1610, 2128), each reagent enclosure (214, 1110, 1610, 2128) including a reagent container (1120, 1620) including a reagent and an internal cavity (1320, 1820) defining a compressible volume, a passage (1230, 1330, 1510) defined through the reagent container (1120, 1620) to the internal cavity (1320, 1820); connecting a plurality of fluid ports (810, 1906, 1908, 1910, 1912, 1914) to the openings of the plurality of reagent enclosures (1110, 1610, 2128); applying a solution through the fluid ports (810, 1906, 1908, 1910, 1912, 1914) to at least partially fill the plurality of reagent enclosures (214, 1110, 1610, 2128); cycling a pressure of the cavity through a gas port fluidically communicating the cavity with an exterior of the cartridge (102, 202, 804, 1900), whereby for each of the reagent enclosures (214, 1110, 1610, 2128), during increasing pressure, the solution enters the internal cavity (1320, 1820) of the reagent container (1120, 1620), combines with the reagent, and compresses the compressible volume, and during decreasing pressure, the compressible volume decreases and the reagent is ejected through the passage (1230, 1330, 1510), and reading an identification tag of the cartridge (102, 202, 804, 1900) with the instrument (100, 200).