Lifescan Corporation

Other

Geoffery McGarraugh

Roger C Phillips

Franklin A Jurik

Raymond D Underwood

Ray Underwood

Frank Jurik

A method for determining the presence of an analyte in a fluid is described along with various components of an apparatus specifically designed to carry out the method. The method involves taking a reflectance reading from one surface of an inert porous matrix impregnated with a reagent that will interact with the analyte to produce a light-absorbing reaction product when the fluid being analyzed is applied to another surface and migrates through the matrix to the surface being read. Reflectance measurements are made at two separate wavelengths in order to eliminate interferences, and a timing circuit is triggered by an initial decrease in reflectance by the wetting of the surface whose reflectance is being measured by the fluid which passes through the inert matrix. Repeatability is insured by a normalization technique performed on the light source before each reading, and an alignment method operated on the reagent strip prior to emplacement on the apparatus. The method and apparatus are particularly suitable for the measurement of glucose levels in blood without requiring separation of red blood cells from serum or plasma.

Reagents test strip adapted for receiving an unmeasured sample while in use in an apparatus

A method for determining the presence of an analyte in a fluid is described along with various components of an apparatus specifically designed to carry out the method. The method involves taking a reflectance reading from one surface of an inert porous matrix impregnated with a reagent that will interact with the analyte to produce a light-absorbing reaction product when the fluid being analyzed is applied to another surface and migrates through the matrix to the surface being read. Reflectance measurements are made at two separate wavelengths in order to eliminate interferences, and a timing circuit is triggered by an initial decrease in reflectance by the wetting of the surface whose reflectance is being measured by the fluid which passes through the inert matrix. Repeatability is insured by a normalization technique performed on the light source before each reading, and an alignment method operated on the reagent strip prior to emplacement on the apparatus. The method and apparatus are particularly suitable for the measurement of flucose levels in blood without requiring separation of red blood cells from serum or plasma.

Method for the determination of glucose employing an apparatus emplaced matrix

A method for determining the presence of an analyte in a fluid is described along with various components of an apparatus specifically designed to carry out the method. The method involves taking a reflectance reading from one surface of an inert porous matrix impregnated with a reagent that will interact with the analyte to produce a light-absorbing reaction product when the fluid being analyzed is applied to another surface and migrates through the matrix to the surface being read. Reflectance measurements are made at two separate wavelengths in order to eliminate interferences, and a timing circuit is triggered by an initial decrease in reflectance by the wetting of the surface whose reflectance is being measured by the fluid which passes through the inert matrix. The method and apparatus are particularly suitable for the measurement of glucose levels in blood without requiring separation of red blood cells from serum or plasma.

Minimum procedure system for the determination of analytes

A reagent test strip for use in an apparatus for determining a blood glucose concentration of a sample of whole blood, the apparatus having optics for detecting intensity of light reflected from a reading surface portion of the reagent test strip. The reagent test strip includes a sample receiving surface portion for receiving an unmetered whole blood sample, a reading surface portion, other than the sample receiving surface portion, from which reflectance is read by the apparatus: and a notch for aligning the reagent test strip in the apparatus.

Reagents test strip with alignment notch

Apparatus for determinating the concentration of glucose in whole blood

A method for measuring analyte concentration in a body fluid involves taking reflectance readings from a first surface of a porous reagent-containing matrix both before and after a sample of the fluid has been applied to a second surface of the matrix. A sequence of reflectance measurements is initiated upon a predetermined drop in reflectance, which indicates that sample has reached the first surface. The analyte concentration is calculated from the sequence of reflectance measurements.

Reflectance measurement of analyte concentration with automatic initiation of timing

A method for determining the presence of an analyte in a fluid is described along with various components of an apparatus specifically designed to carry out the method. The method involves taking a reflectance reading from one surface of an inert porous matrix impregnated with a reagent that will interact with the analyte to produce a light-absorbing reaction product when the fluid being analyzed is applied to another surface and migrates through the matrix to the surface being read. Reflectance measurements are made at two separate wavelengths in order to eliminate interferences, and a timing circuit is triggered by an initial decrease in reflectance by the wetting of the surface whose reflectance is being measured by the fluid which passes through the inert matrix. Repeatability in insured by a normalization technique performed on the light source before each reading, and an alignment method operated on the reagent strip prior to emplacement on the apparatus. The method and apparatus are particularly suitable for tho measurement of flucose levels in blood without requiring separation of red blood cells from serum or plasma.

Temperature-Independent Blood Glucose Measurement

A method for measuring a glucose concentration in whole blood uses a reagent test strip having a matrix pad and a reflectance meter. The test strip is placed in the meter, and a blood sample is applied to the top surface of the pad. As the sample travels through the pad, glucose in the blood reacts with reagent in the pad to cause a change in reflectance of its bottom surface. An incubation period is initiated when the meter detects that at least a portion of the sample has reached the bottom surface. At the end of the incubation period, the reflectance of the bottom surface is measured and used to calculate the glucose concentration.

Automatic initiation of a time interval for measuring glucose

A whole blood glucose test strip for measuring glucose in an unmeasured whole blood sample which does not require removal of excess sample, and which is adapted for use in a reflectance reading apparatus which measures reflectance at about 635 nm and about 700 nm, the test strip comprising a handle having an aperture defined therein; and a porous, hydrophilic matrix disposed over the aperture such that one surface of the matrix is exposed to the atmosphere adjacent to one side of the strip and the other surface of the matrix is exposed to the atmosphere on the other side of the strip through the aperture, one of the surfaces being an upper sample receiving surface adapted to receive the whole blood sample on one side of the matrix and the second of the surfaces being a lower testing surface from which diffuse reflected light is measurable, the testing surface being opposite to the sample receiving surface. The matrix allows the blood color of the blood sample to be observed from the testing surface, allows at least a portion of the blood sample to penetrate through the matrix from the sample receiving surface to the testing surface, and filters out red blood cells such that they do not reach the testing surface. The matrix comprises reagent means for chemically reacting with glucose to create a change in reflectance which is indicative of the concentration of glucose present in the sample.

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Scotts Valley, CA, United States of America

Geoffery McGarraugh