Retic-Chex Linearity is an assayed linearity control kit used to verify patient reportable ranges and measure the linear performance of automated and semi-automated hematology analyzers that report the reticulocyte parameter. The accuracy of hematology instruments can be verified by comparing the laboratory’s reportable range with the Retic-Chex Linearity assays. The assays include instrument specific values for reticulocyte percentages. Verification may be necessary whenever a new instrument is introduced into the lab, when the daily controls reflect an unusual trend or shift outside of the laboratory’s acceptable limits or when major preventative maintenance occurs or essential parts are replaced. Retic-Chex Linearity is packaged in five-vial sets and is available in 2.5 mL and 3.0 mL cap-pierceable vials. It is assayed for Sysmex and Beckman Coulter hematology analyzers.