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Visual blood glucose concentration test strip

  • US 5,306,623 A
  • Filed: 07/26/1991
  • Issued: 04/26/1994
  • Est. Priority Date: 08/28/1989
  • Status: Expired due to Term
First Claim
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1. A reagent strip comprising:

  • a porous matrix having sample side and a test side, said matrix uniformly impregnated with a separation coating and a testing reagent;

    an upper support member upon which the matrix is mounted, having a slit which extend through the upper support member and permits visual observation of the test side;

    a lower support member having a hole therethrough, said lower support member and said upper support member substantially surrounding the matrix;

    said lower support member and said matrix defining a capillary gap therebetween which communicates with the hole and with a portion of the sample side opposite the slit;

    said matrix having a pore size distribution suited to accept a whole blood sample suspected of containing glucose as an analyte applied onto said sample side via the hole and to pass said sample toward said test side by capillary actions;

    said separation coating capable of separating from said whole blood a substantially clear component fluid containing said glucose by selectively retarding the passage of red blood cells through the matrix;

    said testing reagent comprising an enzyme, a dye indicator, and a dye inhibitor capable of reacting with said glucose in said clear component fluid to vary coloration of the test side of said matrix, dependent upon the concentration level of the glucose in said fluid;

    wherein said separation coating is selected from the group consisting of polyvinyl sulfonic acid, polyethylene glycol, polystyrene sulfonic acid, hydroxypropyl cellulose, polyproplene glycol, polyvinyl pyrrolidone and polyacrylic acid; and

    said indicator and said inhibitor are present together on said matrix in bands, such that each band corresponds to one of two or more predetermined glucose concentrations and the presence of glucose concentrations in said whole blood sample which are equal to or greater than said predetermined concentrations may be detected by inspecting each band on the test side though said slit for variations in coloration.

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