A method of detecting the presence or absence of a pipette tip within a pipette sheath of a unitized reagent strip, comprising: providing the unitized reagent strip, the unitized reagent strip, comprising: a strip with a top side and a bottom side, comprising: a first and a second pipette sheath comprising opposing sides, the first and second pipette sheaths comprising a first and second pipette tip aperture, respectively, each of which comprises a separate opening on the top side of the strip, wherein the first and second pipette tip apertures are configured for insertion of a first and second pipette tip into the first and second pipette sheaths, respectively, and wherein each of the first and second pipette sheaths is configured to substantially surround the length of a first and second pipette tip, respectively, and wherein the first pipette sheath comprises a first cored hole, the first cored hole extending through a sidewall of the first pipette sheath; a process tube, wherein the process tube is integral with the strip or separate from the strip; and a reagent tube integral with the strip or a receptacle, comprising an opening through the strip, wherein the receptacle is configured to receive the reagent tube; determining whether a pipette tip extends within the first pipette sheath from the pipette tip aperture at least to the distance of the first cored hole, comprising: providing an optical beam that enters the first pipette sheath through the first cored hole, and determining the reflection or obstruction of the optical beam as indicative of the presence or absence of a pipette tip that extends within the first pipette sheath to the distance from the pipette tip aperture to the first cored hole. providing the unitized reagent strip, the unitized reagent strip, comprising: a strip with a top side and a bottom side, comprising: a first and a second pipette sheath comprising opposing sides, the first and second pipette sheaths comprising a first and second pipette tip aperture, respectively, each of which comprises a separate opening on the top side of the strip, wherein the first and second pipette tip apertures are configured for insertion of a first and second pipette tip into the first and second pipette sheaths, respectively, and wherein each of the first and second pipette sheaths is configured to substantially surround the length of a first and second pipette tip, respectively, and wherein the first pipette sheath comprises a first cored hole, the first cored hole extending through a sidewall of the first pipette sheath; a process tube, wherein the process tube is integral with the strip or separate from the strip; and a reagent tube integral with the strip or a receptacle, comprising an opening through the strip, wherein the receptacle is configured to receive the reagent tube; a first and a second pipette sheath comprising opposing sides, the first and second pipette sheaths comprising a first and second pipette tip aperture, respectively, each of which comprises a separate opening on the top side of the strip, wherein the first and second pipette tip apertures are configured for insertion of a first and second pipette tip into the first and second pipette sheaths, respectively, and wherein each of the first and second pipette sheaths is configured to substantially surround the length of a first and second pipette tip, respectively, and wherein the first pipette sheath comprises a first cored hole, the first cored hole extending through a sidewall of the first pipette sheath; a process tube, wherein the process tube is integral with the strip or separate from the strip; and a reagent tube integral with the strip or a receptacle, comprising an opening through the strip, wherein the receptacle is configured to receive the reagent tube; determining whether a pipette tip extends within the first pipette sheath from the pipette tip aperture at least to the distance of the first cored hole, comprising: providing an optical beam that enters the first pipette sheath through the first cored hole, and determining the reflection or obstruction of the optical beam as indicative of the presence or absence of a pipette tip that extends within the first pipette sheath to the distance from the pipette tip aperture to the first cored hole. providing an optical beam that enters the first pipette sheath through the first cored hole, and determining the reflection or obstruction of the optical beam as indicative of the presence or absence of a pipette tip that extends within the first pipette sheath to the distance from the pipette tip aperture to the first cored hole.