Analytical cartridge and system for detecting analytes in liquid samples

A diagnosis system, which comprises a monitor, comprising a detector providing multiple reflectance readings in an array of individual locations, registering an analytical cartridge in the monitor at a fixed location and orientation relative to the array, and determines and displays analytical results from reflectance readings; and an analytical cartridge, comprising a liquid impervious housing, a sample application site in the housing located outside the monitor when the cartridge is registered in the monitor by the means for registering, one or more reflectance reading sites in the housing that register with one or more of the locations in the array, a capillary pathway in the housing leading from the sample application site to each of the reflectance reading sites, and a reflectance matrix located in at least one of the reflectance reading sites. In some embodiments of the invention, control features that optimize accuracy of measurement by controlling when and if sample reaches reflectance reading sites and by drawing excess sample away from undesirable locations in the cartridge are present. One control element balances the liquid-holding capacities of the application site, the sample-transporting capillary passageway that leads to the reflectance reading site, and the porous matrices from which the reflectance reading will be made, so that excess sample is excluded from entry into the cartridge while sample volumes that are below the minimum necessary for accurate operation do not reach the matrix, thereby avoiding false readings.