Lifescan Corporation

Edward G Rice

Michael F Tomasco

Ernest J Kiser

Yeung Siu Yu

Joel Sterling Douglas

Remedios Dato

Koon-Wah Leong

Maria Teodorczyk

Scott Segelke

Deborah P Tuohy

Tahir Sadik Khan

Mark Maxson

Zbigniew Witko

Karen R Drexler

Jennifer Hahamian

Victoria Page

Methods for making reagent test strips are provided. In the subject methods, a test strip precursor made up of an elongated support material having a planar surface and a narrow stripe of reagent material positioned along its central axis is cut according to an inter-digitating pattern to produce the plurality of reagent test strips. The initial precursor material may be a tape or in the form of a card. Also provided are the reagent test strips produced by the subject methods and kits that include the same. The subject reagent test strips and kits find use in analyte detection and/or concentration determination assays.

Methods of manufacturing reagent test strips

A reagent test strip for measuring an analyte concentration in a biological fluid has a spreading mesh sandwiched between a support and a reagent matrix. The support has a through hole that is covered by the mesh. In use, a sample of the fluid is applied through the hole in the support to the spreading mesh. The sample then passes through the mesh to the matrix, which contains a reagent that indicates the analyte concentration by causing a corresponding change in reflectance at its free surface. Optionally, an adhesive layer attaches the mesh, and optionally the matrix as well, to the support.

Multi-layer reagent test strip

A multilayer reagent test strip measures the concentration of analyte in a liquid sample that is applied to it. The sample is guided to a number of assay areas arrayed along the strip, where the analyte can react with a reagent to cause a color change. Each assay area also includes an inhibitor for the color-change reaction. The inhibitor concentration increases in successive assay areas; thus, the number of areas that change color is a measure of the analyte concentration. The test strip is particularly adapted for measuring glucose in a whole blood sample. In a preferred embodiment, the sample is guided to the assay areas along a path formed by crushing selected areas of a membrane, and the assay areas are uncrushed areas of the membrane.

Visually-readable reagent test strip

A chemical timer for a direct-reading reagent test strip changes color a predetermined time after a biological fluid is applied to the strip. The strip measures the concentration of an analyte in the fluid. The timer is a dry coating of an indicator, an enzyme-containing reagent that when hydrated can react with glucose to change the color of the indicator, an inhibitor to inhibit the change in color of the indicator, glucose, and optionally, an aldose that does not react with the enzyme in the reagent. Preferably, the reagent and glucose are present in excess in the coating, and the time it takes for the timer color to change can be controlled by the inhibitor concentration. The aldose provides timer stability, probably by interfering with glycosylation by the glucose in the dry state.

Chemical timer for a visual test strip

Visual test strip

A reagent strip for measuring glucose concentration in a biological fluid containing red blood cells has reduced interference of hematocrit with the glucose measurement. When a biological fluid contacts the strip, it causes, in a reagent impregnated in the strip, a color change which is a measure of the glucose concentration in the fluid. However, the color change is also affected by the red blood cell concentration (hematocrit), thereby reducing the accuracy of the glucose measurement. The hematocrit effect is reduced by adding to the reagent a component, such as imidazole or imidazole and N-acetylglucosamine, for minimizing side reactions of the glucose, or its reaction products, with the fluid.

Blood glucose strip having reduced side reactions

A separation matrix impregnated with a separating agent separates red blood cells or hemoglobin from whole blood. Upon separation, an impregnated test reagent reacts with the separated substantially clear component fluid to form a colored product which enables a visual or meter test for glucose levels in whole blood.

Glucose test strip for whole blood

A separation matrix impregnated with a separating agent separates red blood cells or hemoglobin from whole blood. Upon separation, an impregnated test reagent reacts with the separated substantially clear component fluid to form a colored product which enables a visual or meter test for analyte levels in whole blood. Such a test is appropriate for, among other things measuring glucose, cholesterol, or alcohol levels in whole blood samples. A visual meter is disclosed which allows sample to be applied to one side of the strip, and reading takes place on the opposite side, after separation of red blood cells and reaction to test reagent. Also, a useful test strip format is disclosed.

Growing community of inventors

Palo Alto, CA, United States of America

Edward G Rice