# US 2019/0169674 A1 · METHOD FOR MEASURING HbA1c

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- Number: US 2019/0169674 A1
- Document ID: US20190169674A1
- Status: Published application
- Kind: A1
- Application number: 16/324,414
- Filed: 2017-08-10
- Published: 2019-06-06
- Earliest claimed: 2016-08-10
- Assignees: Sekisui Medical Co., Ltd.
- Applicants: Sekisui Medical Co., Ltd.
- Inventors: Satoshi MACHIDA; Tomohisa NISHIO; Kazuo NAKANISHI
- Web page: https://patentgrep.com/patent/US20190169674A1

## CPC

- C12Q 1/37: involving peptidase or proteinase
- G01N 21/27: using photo-electric detection (G01N21/31 takes precedence){; circuits for computing concentration (logarithmic circuits G06G7/24; photometric circuits in general G01J)}
- G01N 21/31: Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry {(G01N21/72 takes precedence)}
- G01N 21/59: Transmissivity (G01N21/25 takes precedence)
- G01N 33/72: involving blood pigments, e.g. haemoglobin, bilirubin {or other porphyrins; involving occult blood}
- G01N 33/721: {Haemoglobin}
- G01N 2333/92: Triglyceride splitting, e.g. by means of lipase
- C12Q: MEASURING OR TESTING PROCESSES INVOLVING ENZYMES, NUCLEIC ACIDS OR MICROORGANISMS (immunoassay G01N33/53); COMPOSITIONS OR TEST PAPERS THEREFOR; PROCESSES OF PREPARING SUCH COMPOSITIONS; CONDITION-RESPONSIVE CONTROL IN MICROBIOLOGICAL OR ENZYMOLOGICAL PROCESSES
- G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q)

## Abstract

Provided is a method of avoiding the influence of a coexisting substance in the measurement of HbA1c % for a whole blood sample by an enzymatic method. Specifically, provided is a method of measuring a ratio of a hemoglobin A1c concentration to a hemoglobin concentration in a sample by an enzymatic method, the method including: a first step of optically measuring the hemoglobin concentration; and a second step of optically measuring the hemoglobin A1c concentration, wherein, when HbA1c % is calculated by dividing the hemoglobin A1c concentration measured in the second step by the hemoglobin concentration measured in the first step, the hemoglobin concentration serving as a denominator, which is measured at a first wavelength, is corrected using a result measured at a second wavelength.

## Claims

### Claim 1

A method of measuring a ratio of a hemoglobin A1c concentration to a hemoglobin concentration in a sample by an enzymatic method, the method comprising:
a first step of optically measuring the hemoglobin concentration; and
a second step of optically measuring the hemoglobin A1c concentration,
wherein, when HbA1c % is calculated by dividing the hemoglobin A1c concentration measured in the second step by the hemoglobin concentration measured in the first step, the hemoglobin concentration serving as a denominator, which is measured at a first wavelength, is corrected using a result measured at a second wavelength that satisfies the following conditions:
a longer wavelength than 480 nm;
a wavelength that gives an absorbance equal to or less than 1/10 of an absorbance at 480 nm for a 100 μmol/L solution of hemoglobin in physiological saline; and
a wavelength at which a correlation exists between a fat particle concentration and an absorbance.

### Claim 2

A method of measuring a ratio of a hemoglobin A1c concentration to a hemoglobin concentration in a sample by an enzymatic method, the method comprising:
a first step of optically measuring the hemoglobin concentration; and
a second step of optically measuring the hemoglobin A1c concentration,
wherein, when HbA1c % is calculated by dividing the hemoglobin A1c concentration measured in the second step by the hemoglobin concentration measured in the first step, the hemoglobin concentration serving as a denominator, which is measured by a first wavelength selected from 450 nm to 610 nm, is corrected using a result measured at a second wavelength selected from 690 nm to 900 nm.

### Claim 3

A method of measuring a ratio of a hemoglobin A1c concentration to a hemoglobin concentration in a sample by an enzymatic method,
the hemoglobin concentration being optically measured in a first step,
the hemoglobin A1c concentration being optically measured in a second step,
wherein, when HbA1c % is calculated by dividing the hemoglobin A1c concentration measured in the second step by the hemoglobin concentration measured in the first step, the hemoglobin concentration serving as a denominator, which is measured at a first wavelength selected from 450 nm to 610 nm, is corrected using concentration information on lipid particles and concentration information on hemoglobin that are measured at a second wavelength selected from 690 nm to 900 nm.