Abstract: Methods and systems for collecting cells on a filter disposed in a specimen fluid containing suspended cells of a biological specimen. A short vacuum pulse is applied across a filter to sip specimen fluid. A percentage or portion of the filter surface area covered by cells is determined is representative of or correlates to the density of cells in the specimen fluid. A maximum vacuum amplitude and/or duration are determined utilizing the determined filter coverage. A longer, continuous vacuum or slurp is applied across the filter to collect cells on the filter while limiting the amplitude and/or duration of the slurp based at least in part upon the determined maximum vacuum amplitude and/or duration.

Abstract: An apparatus for processing a specimen from a fluid sample includes a first set of one or more microfluidic channels configured to deliver the sample fluid to a filter disposed on an inflatable bladder configured to transfer the specimen from the filter to a slide. The apparatus is configured to collect an approximate monolayer of particles and includes a second set of one or more microfluidic channels configured to remove fluid flowing through the filter disposed on the inflatable bladder. The apparatus also includes a pressure source, a sample container connected to the pressure source and the first set of one or more microfluidic channels, a fluid flow gauge configured to measure a fluid flow rate through the filter, and a stain source connected to the first set of one or more microfluidic channels.

Abstract: A system and method for determining an in vivo property of a tissue or blood is described. The in vivo property may be a hematocrit value, a hemoglobin concentration, or a combination thereof. The system can automatically determine a location of a subcutaneous blood vessel. Based on the automatically determined location, the system illuminates the blood vessel with a light beam and detects light resulting from the illumination. The system determines the in vivo property based on the detected light. Alternatively, or in combination, the system displays an image corresponding to a spatial relationship between a subcutaneous blood vessel and a light beam. Based on the image, an operator can adjust the light beam with respect to the blood vessel to have a selected spatial relationship. The system determines an in vivo property based on the illumination of the blood vessel when the light beam has the selected spatial relationship.