Provided is a composition by which glycated hemoglobin can be measured even in the presence of a stronger surfactant than a conventional case. Also provided is a buffer and/or stabilizer which maintains the residual activity of an amadoriase or lowers a reduction of residual activity. The present invention provides a composition for use in measuring glycated hemoglobin containing an amadoriase having substitution of one or more amino acid residues at a position(s) corresponding to an amino acid(s) selected from the group consisting of position 262, position 257, position 249, position 253, position 337, position 340, position 232, position 129, position 132, position 133, position 44, position 256, position 231 and position 81 of an amadoriase derived from the genus Coniochaeta and represented by SEQ ID No: 1 or 3, and having residual activity even in the presence of a surfactant. The present invention also provides a composition and kit for use in measuring glycated hemoglobin, comprising a specific stabilizer and/or a buffer. The present invention can provide an enzyme and a composition for use in measuring glycated hemoglobin, excellent in storage stability even if they are exposed to a surfactant.

A diagnostic system detects and/or measures hemoglobin variants in blood of subject, such as HbA1c, to determine blood glucose concentration in the subject.

Provided is a catalase inhibitor comprising a compound represented by formula (I): ##STR00001##
wherein R.sub.1 to R.sub.4 independently represent a hydrogen atom, a halogen atom, an amino group, a hydroxyl group, a carbonyl group, or a hydrocarbon group having 1 to 4 carbon atoms, wherein the hydrocarbon group may have at least one substituent selected from the group consisting of a halogen atom, an amino group, a hydroxyl group and a carbonyl group; and X.sup. represents an anionic chemical species.

This invention provides an amadoriase that can react with a wide variety of glycated peptides generated upon hydrolysis of the chain of hemoglobin A1c (HbA1c) to generate hydrogen peroxide, a method for measurement of HbA1c using such amadoriase, and a reagent kit for measurement of HbA1c using such amadoriase. Provided is an amadoriase obtained by substitution of one or more amino acids at positions corresponding to amino acids selected from the group consisting of amino acids 62, 63, 102, 106, 110, 113, and 355 in the amino acid sequence of the amadoriase derived from the genus Coniochaeta or the like which amadoriase is capable of oxidizing a wide variety of glycated peptides to generate hydrogen peroxide. Further provided is a method for measurement of HbA1c comprising using such amadoriase as well as a reagent kit for measurement of HbA1c comprising such amadoriase. This invention can provide a method for measurement of HbA1c that enables quantification of HbA1c to be performed rapidly, simply, and accurately with the use of a small amount of a protease and a kit used for such measurement. This invention can also provide a method for measurement of HbA1c that enables quantification of HbA1c to be performed rapidly, simply, and accurately, with high sensitivity with the use of a small amount of a protease and a kit used for such measurement.

A method is provided for measuring glycated hemoglobin in a hemoglobin-containing sample which comprises: adding an enzyme that catalyzes a reaction of oxidizing glycated amino acid or glycated peptide to generate hydrogen peroxide without oxidizing the glycated hemoglobin, to the hemoglobin-containing sample to generate hydrogen peroxide; eliminating the generated hydrogen peroxide; adding an enzyme that catalyzes a reaction of oxidizing glycated hemoglobin to generate hydrogen peroxide thereto to generate hydrogen peroxide; and measuring the generated hydrogen peroxide.

Devices, kits, and methods related to embodiments of an improved liquid test sample injection device for use in diagnostic assays and for the collection of liquid waste produced from such diagnostic assays.

The present description relates to a method for identifying a patient who is eligible for an intensification of heart failure therapy. Furthermore, the description relates to a method for optimizing B type natriuretic peptide (BNP) and/or N-terminal pro B-type natriuretic peptide (NT-proBNP)-type peptide guided heart failure therapy. The methods are based on the measurement of the level of at least one marker in a sample from a patient who has heart failure and who receives B-type natriuretic peptide (BNP) and/or N-terminal pro B-type natriuretic peptide (NT-proBNP)-type peptide guided heart failure therapy. Further described are kits and devices adapted to carry out the described method.

A system for testing for an analyte includes a test strip. The test strip includes a test strip detection conductor. The test strip includes a first flow path, the first flow path including a heating area, the test strip detection conductor in the heating area, the test strip detection conductor configured to be activated to heat a sample in the heating area.

A method is disclosed comprising lysing the red blood cells of a whole blood sample, oxidizing the free hemoglobin in the lysed sample, and cleaving FVH from the hemoglobin A1C to form an electrochemical test solution. In one aspect, a first portion of the electrochemical test solution is reacted with fructosyl peptide oxidase and a reduced ruthenium mediator to form a first reaction product. A first electrical property of the first reaction product is measured, the measurement being indicative of hemoglobin A1C in the blood sample. In another aspect, a second portion of the electrochemical test solution is reacted with ferrocyanide to form a second reaction product. A second electrical property of the second reaction product is measured, the measurement being indicative of total hemoglobin in the blood sample. Hemoglobin A1C, total hemoglobin, and % HbA1C are determined based on the first and second electrical properties. Also provided are systems and components useful in performing the disclosed methods.

A system for determining a concentration of hemoglobin A1C includes a first lateral flow test strip, the first lateral flow test strip providing for a percent of HbA1C concentration; a second lateral flow test strip, the second lateral flow test strip providing for the total amount of hemoglobin; an antibody-microparticle stripe on each of the first and second lateral flow test strips; a conjugate stripe on each of the first and second lateral flow test strips; and a sample treatment buffer. The sample treatment buffer is strongly denaturing, and antibodies in the antibody-microparticle strip are covalently bound to microparticles.