title: Hematocrit analysis through the use of an inexpensive centrifugal polyester-toner device with finger-to-chip blood loading capability.
abstract: Hematocrit (HCT) measurements are important clinical diagnostic variables that help physicians diagnose and treat various medical conditions, ailments, and diseases. In this work, we present the HCT Disc, a centrifugal microdevice fabricated by a Print, Cut and Laminate (PCL) method to generate a 12-sample HCT device from materials costing <0.5 USD (polyester and toner or PeT). Following introduction from a drop of blood (finger stick), whole blood metering and cell sedimentation are controlled by centrifugal force, only requiring a CD player motor as external hardware and, ultimately, a cell phone for detection. The sedimented volume from patient blood in the HCT Disc was analyzed using a conventional scanner/custom algorithm for analysis of the image to determine a hematocrit value, and these were compared to values generated in a clinical laboratory, which correlated well. To enhance portability and assure simplicity of the HCT measurement, values from image analysis by a cell phone using a custom application was compared to the scanner. Fifteen samples were analyzed with cell phone image analysis system and were found to be within 4% of the HCT values determined in the clinical lab. We demonstrate the feasibility of the PeT device for HCT measurement, and highlight its uniquely low cost (<0.5 USD), speed (sample-to-answer <8 min), multiplexability (12 samples), low volume whole blood requirement (<3 μL), rotation speeds (<4000 rpm) needed for effective measurement as well as the direct finger-to-chip sample loading capability.
authors.affiliation: Department of Chemistry, McCormick Road, University of Virginia, Charlottesville, VA 22904, USA.
authors.forename: Brandon L
authors.initials: BL
authors.lastname: Thompson
authors.affiliation: Department of Chemistry, McCormick Road, University of Virginia, Charlottesville, VA 22904, USA.
authors.forename: Rachel J
authors.initials: RJ
authors.lastname: Gilbert
authors.affiliation: Department of Mechanical Engineering, Engineer's Way, University of Virginia, Charlottesville, VA 22904, USA.
authors.forename: Maximo
authors.initials: M
authors.lastname: Mejia
authors.affiliation: Department of Computer Science, Engineer's Way, University of Virginia, Charlottesville, VA 22904, USA.
authors.forename: Nishant
authors.initials: N
authors.lastname: Shukla
authors.affiliation: Department of Pathology, University of Virginia Health Science Center, Charlottesville, VA 22908, USA.
authors.forename: Doris M
authors.initials: DM
authors.lastname: Haverstick
authors.affiliation: Department of Mechanical Engineering, Engineer's Way, University of Virginia, Charlottesville, VA 22904, USA.
authors.forename: Gavin T
authors.initials: GT
authors.lastname: Garner
authors.affiliation: Department of Chemistry, McCormick Road, University of Virginia, Charlottesville, VA 22904, USA; Department of Mechanical Engineering, Engineer's Way, University of Virginia, Charlottesville, VA 22904, USA; Department of Pathology, University of Virginia Health Science Center, Charlottesville, VA 22908, USA. Electronic address: landers@virginia.edu.
authors.forename: James P
authors.initials: JP
authors.lastname: Landers
mesh_terms: D040421:Cell Phone; D002498:Centrifugation / Q000295:instrumentation; D004867:Equipment Design; D006400:Hematocrit / Q000191:economics / Q000295:instrumentation*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D011091:Polyesters / Q000737:chemistry*; D013997:Time Factors
chemical_list: D011091:Polyesters
keywords: Cell phone detection; Centrifugal microfluidics; Hematocrit; Polyester-toner