EP0085263A1
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Method and reagent for determining glucose levels in blood samples
Assignee: F Hoffmann La Roche AG
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Filing: 1982-12-22
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Granted: —
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Expires: 2002-12-22
Abstract
Abstract The invention provides a method of determining serum glucose levels in a blood sample or a sample derived from blood, said method comprising the steps of maintaining the sample at a controlled temperature, controlling the pH of the sample to a suitable value, between 10 and 14, adding a colouring agent, preferably a reducible dye such as nitro-blue tetrazolium, to the sample and after a first delay in taking a first colour measurement and after a second delay in time taking a second colour measurement and comparing the resultant colour change with the colour change in a standard solution, the selected colouring agent and pH conditions being such that a change of colour in the colouring agent is caused by the glucose in the sample while that glucose is still reacted or associated with an amine group of protein in that blood and when the glucose has undergone a molecular re-arrangement and is present in the form of fructosamine.
Inventors
- 👤 John Richard Baker
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-06 08:04
CPC Classifications
G; G01; G01N; G01N33/00; G01N33/48; G01N33/50; G01N33/66; Y; Y10; Y10S; Y10S436/00; Y10S436/904; Y10T; Y10T436/00; Y10T436/10; Y10T436/104998; Y10T436/105831; Y10T436/14; Y10T436/142222; Y10T436/143333; Y10T436/144444
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
148 words
A method of determining serum glucose levels in a blood sample or a sample derived from blood, said method comprising the steps of maintaining the sample at a controlled temperature, controlling the pH of the sample to a suitable value, between 10 and 14, adding a colouring agent to the sample and after a first delay in taking a first colour measurement and after a second delay in time taking a second colour measurement and comparing the resultant colour change with the colour change in a standard solution, the selected colouring agent and pH conditions being such that a change of colour in the colouring agent is caused by the glucose in the sample while that glucose is still reacted or associated with an amine group of protein in that blood and when the glucose has undergone a molecular re-arrangement and is present in the form of fructosamine.
Claim 2
Independent Claim
148 words
A method of determining serum glucose levels in a blood sample or a sample derived from blood, said method comprising the steps of maintaining the sample at a controlled temperature, controlling the pH of the sample to a suitable value, between 10 and 14, adding a colouring agent to the sample and after a first delay in taking a first colour measurement and after a second delay in time taking a second colour measurement and comparing the resultant colour change with the colour change in a standard solution, the selected colouring agent and pH conditions being such that a change of colour in the colouring agent is caused by the glucose in the sample while that glucose is still reacted or associated with an amine group of protein in that blood and when the glucose has undergone a molecular re-arrangement and is present in the form of fructosamine.
Claim 3
Dependent Claim
16 words
A method as claimed in claim 1 wherein said pH level lies between 10.5 and 10.8.
Claim 4
Dependent Claim
20 words
A method as claimed in claim 1 wherein said pH level is adjusted by adding a buffer to the sample.
Claim 5
Dependent Claim
20 words
A method as claimed in claim 3 in which said buffer comprises sodium carbonate and sodium bicarbonate in suitable proportions.
Claim 6
Independent Claim
24 words
A method as claimed in any one of the preceding claims wherein said colouring agent is a dye which changes colour on being reduced.
Claim 7
Dependent Claim
14 words
A method as claimed in claim 5 wherein said dye is a tetrazolium salt.
Claim 8
Dependent Claim
57 words
A method as claimed in claim 5 or 6 wherein the colour absorbance is first measured at about 530nm 5-10 minutes after a test has commenced and again 8-15 minutes after said test was commenced and the colour compared with one or more standard of which the relationship between glucose level and colour level is substantially known.
Claim 9
Independent Claim
21 words
A method as claimed in any one of the preceding claims wherein said standards comprise a protein and a synthetic fructosamine.
Claim 10
Dependent Claim
24 words
A method as claimed in claim 8 wherein said standards comprise aliquots of an aqueous solution of deoxymorpholinofructose (DMF) added to an albumin solution.
Claim 11
Independent Claim
20 words
A method as claimed in any one of the preceding claims wherein the test is carried out at about 37°C.
Claim 12
Independent Claim
33 words
A method as claimed in any one of claims 1 to 9 wherein the steps are carried out at about 45 c C in a automatic testing apparatus on a series of samples.
Claim 13
Dependent Claim
43 words
A reagent for use in a method as claimed in any one of the preceding claims comprising a buffer and a colouring agent which changes colour over a period of time after the buffer and colouring agent have been added to the sample.
Claim 14
Dependent Claim
23 words
A standard solution for use in the method of claim 8 or 9, said standard solution comprising a protein and a synthetic fructosamine.
Claim 15
Dependent Claim
12 words
A standard solution as claimed in claim 13 comprising albumin and deoxymorpholinofructose.
Claim 16
Independent Claim
42 words
A method of detecting diabetes mellitus in human beings, which comprises determining serum glucose levels in a patient by the method of any of claims 1 to 11, and comparing the readings obtained with standards representative of known stages of diabetes mellitus.
References Cited (Backward Citations)
US3791988A
Cited
WO1982001804A1
Cited
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