US-20260125737-A1 - REAGENT COMPOSITION AND KIT

US20260125737A1US 20260125737 A1US20260125737 A1US 20260125737A1US-20260125737-A1

Abstract

A reagent composition containing an anionic surfactant, in which the reagent composition is used as a first reagent composition in a method for quantifying a sdLDL-C in a sample, the method including acting the first reagent composition on a sample, and subsequently acting a second reagent composition for quantifying the sdLDL-C to quantify cholesterol in a remaining lipoprotein, the reagent composition has cholesterol esterase activity and cholesterol oxidase activity, and also has at least one activity selected from the group made of peroxidase activity and catalase activity, and a contact angle between the reagent composition and a polyethylene terephthalate (PET) base material is equal to or more than 65° and equal to or less than 77°.

Inventors

Yasuki Ito

Assignees

DENKA COMPANY LIMITED

Dates

Publication Date: 20260507
Application Date: 20211102

Claims (10)

1 . A reagent composition comprising: an anionic surfactant, wherein the reagent composition is used as a first reagent composition in a method for quantifying a small dense LDL cholesterol (sdLDL-C) in a sample, the method including, acting the first reagent composition on the sample, and after the acting the first reagent composition on the sample, acting a second reagent composition for quantifying the sdLDL-C to quantify cholesterol in a remaining lipoprotein, the reagent composition has cholesterol esterase activity and cholesterol oxidase activity, and also has at least one activity selected from the group consisting of peroxidase activity and catalase activity, and a contact angle between the reagent composition and a polyethylene terephthalate (PET) base material, which is measured by the following method 1, is equal to or more than 65° and equal to or more than 77°, (method 1) (1) the PET base material: PET (amorphous polyester) resin plate, transparent, thickness of 2 mm, (2) a pre-treatment: a surface of the PET base material unused is wiped with a 70% ethanol aqueous solution, and a measurement is performed within 5 minutes after the wiping, (3) a measurement method and conditions: a liquid droplet method, a θ/2 method, a temperature: 15 to 25° C., a syringe: Teflon-coated 18G, a dropwise addition method, a dropwise addition amount: 2 μL, a measurement 1 second after the dropwise addition, and (4) a calculation of the contact angle: the measurement is performed 5 times, and an average value of the 5 times is obtained.
2 . The reagent composition according to claim 1 , wherein the reagent composition further has ascorbic acid oxidase activity.
3 . The reagent composition according to claim 1 , wherein the reagent composition has no sphingomyelinase activity.
4 . The reagent composition according to claim 1 , wherein the anionic surfactant includes a sulfuric acid ester salt.
5 . The reagent composition according to claim 1 , further comprising: any one of a hydrogen donor and a coupler.
6 . The reagent composition according to claim 1 , wherein a viscosity of the reagent composition at 5° C., which is measured by the following method 2-1, is equal to or less than 2.0 mPa·s, (method 2-1) (1) a device: an Electro Magnetically Spinning (EMS) viscometer, (2) a measurement method and conditions: a measurement type: an electromagnetic spinning method, a motor rotation speed: 1,000 rpm, a holding time: 600 seconds, a measurement temperature: 5° C., a sequence loop: 1 time, a sample: 500 μL, and (3) a calculation of the viscosity: the measurement is performed 5 times, and an average value of the 5 times is calculated.
7 . The reagent composition according to claim 1 , wherein a viscosity of the reagent composition at 37° C., which is measured by the following method 2-2, is equal to or less than 0.89 mPa·s, (method 2-2) (1) a device: an Electro Magnetically Spinning (EMS) viscometer, (2) a measurement method and conditions: a measurement type: an electromagnetic spinning method, a motor rotation speed: 1,000 rpm, a holding time: 600 seconds, a measurement temperature: 37° C., a sequence loop: 1 time, a sample: 500 μL, and (3) a calculation of the viscosity: the measurement is performed 5 times, and an average value of the 5 times is calculated.
8 . A kit used for quantifying a sdLDL-C in a sample, the kit comprising: a first reagent composition consisting of the reagent composition according to claim 1 ; and a second reagent composition for quantifying the sdLDL-C.
9 . The kit according to claim 8 , wherein the second reagent composition has peroxidase activity.
10 . The kit according to claim 8 , wherein the first reagent composition contains any one of a hydrogen donor and a coupler and does not contain the other, and the second reagent composition does not contain the one of the hydrogen donor and the coupler and contains the other.

Description

TECHNICAL FIELD The present invention relates to a reagent composition and a kit. BACKGROUND ART As a technique relating to a method of measuring LDL cholesterol, there is a method disclosed in Patent Document 1 (Japanese Unexamined Patent Publication No. 2000-325097). Patent Document 1 discloses a method for measuring lipoprotein cholesterol, which includes a first step of selectively subjecting HDL cholesterol to an enzyme reaction by adding an enzyme and a first surfactant to a sample containing a lipoprotein, a second step of selectively subjecting LDL cholesterol to an enzyme reaction by adding a second surfactant to the sample, and measuring a compound consumed by a reaction with the enzyme or a compound generated by the reaction in the first or second step to measure HDL cholesterol and/or LDL cholesterol. The method does not require a lipoprotein coagulant which increases a turbidity of a reaction solution, is not limited to the enzyme used, does not require an addition of another enzyme in the step of reacting the LDL cholesterol, can quantitatively measure the LDL cholesterol easily and inexpensively, and can accurately and inexpensively measure the HDL cholesterol without forming a lipoprotein coagulation which interferes with optical measurement. Therefore, the method is particularly useful in the field of clinical tests such as arteriosclerosis. RELATED DOCUMENT Patent Document [Patent Document 1] Japanese Unexamined Patent Publication No. 2000-325097 SUMMARY OF THE INVENTION Technical Problem The present inventor has investigated a measurement of small dense LDL cholesterol (sdLDL-C) among LDL cholesterols. As a result, it has been found that there is room for improvement in terms of measurement accuracy in the technique described in Patent Document 1. The present invention provides a technique for measuring sdLDL-C with excellent accuracy. Solution to Problem The present inventor has conducted investigations to improve the accuracy of quantification of sdLDL-C. As a result, the present inventor has newly found that it is possible to quantify sdLDL-C with excellent accuracy by setting a contact angle of a reagent composition used for quantifying the sdLDL-C within a specific range, and has completed the present invention. According to the present invention, the following reagent composition and kit are provided. [1] A reagent composition containing: an anionic surfactant,in which the reagent composition is used as a first reagent composition in a method for quantifying a small dense LDL cholesterol (sdLDL-C) in a sample, the method including,acting the first reagent composition on the sample, andafter the acting the first reagent composition on the sample, acting a second reagent composition for quantifying the sdLDL-C to quantify cholesterol in a remaining lipoprotein,the reagent composition has cholesterol esterase activity and cholesterol oxidase activity, and also has at least one activity selected from the group consisting of peroxidase activity and catalase activity, anda contact angle between the reagent composition and a polyethylene terephthalate (PET) base material, which is measured by the following method 1, is equal to or more than 65° and equal to or more than 77°, (Method 1) (1) the PET base material: PET (amorphous polyester) resin plate, transparent, thickness of 2 mm,(2) a pre-treatment: a surface of the PET base material unused is wiped with a 70% ethanol aqueous solution, and a measurement is performed within 5 minutes after the wiping,(3) a measurement method and conditions: a liquid droplet method, a θ/2 method, a temperature: 15 to 25° C., a syringe: Teflon (registered trademark; the same applies hereinafter)-coated 18G, a dropwise addition method, a dropwise addition amount: 2 μL, a measurement 1 second after the dropwise addition, and(4) a calculation of the contact angle: the measurement is performed 5 times, and an average value of the 5 times is obtained. [2] The reagent composition according to [1], in which the reagent composition further has ascorbic acid oxidase activity. [3] The reagent composition according to [1] or [2], in which the reagent composition has no sphingomyelinase activity. [4] The reagent composition according to any one of [1] to [3], in which the anionic surfactant includes a sulfuric acid ester salt. [5] The reagent composition according to any one of [1] to [4], further containing: any one of a hydrogen donor and a coupler. [6] The reagent composition according to any one of [1] to [5], in which a viscosity of the reagent composition at 5° C., which is measured by the following method 2-1, is equal to or less than 2.0 mPa·s, (Method 2-1) (1) a device: an Electro Magnetically Spinning (EMS) viscometer,(2) a measurement method and conditions: a measurement type: an electromagnetic spinning method, a motor rotation speed: 1,000 rpm, a holding time: 600 seconds, a measurement temperature: 5° C., a sequence loop: 1 time, a sample: 500 μL, and(3)