Single color reading method for determining fructosamine

Claim 1

A method of determining serum glucose levels in a sample of blood or a sample derived from blood, said method being characterised by comprising the steps of eliminating the interfering substances, controlling the pH of the sample to between 10 and 14, adding a coloring agent to the sample and after a delay, taking a color measurement and comparing the resultant color with the color in a standard solution, the selected coloring agent and pH conditions being such that a change of color in the coloring 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 rearrangement and is present in the form of fructosamine.

Claim 2

A method of determining serum glucose levels in a sample of blood or a sample derived from blood, said method being characterised by comprising the steps of eliminating the interfering substances, controlling the pH of the sample to between 10 and 14, adding a coloring agent to the sample and after a delay, taking a color measurement and comparing the resultant color with the color in a standard solution, the selected coloring agent and pH conditions being such that a change of color in the coloring 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 rearrangement and is present in the form of fructosamine.

Claim 3

A method of determining fructosamine levels in a sample, said method comprising the steps of eliminating the interfering substances and controlling the pH of the sample to between 10 and 14, adding a coloring agent to the sample capable of reacting with fructosamine to develop a color and, after a delay, taking a color measurement and comparing the resultant color with the color developed with said coloring agent with a standard fructosamine solution.

Claim 4

A method of determining fructosamine levels in a sample, said method comprising the steps of eliminating the interfering substances and controlling the pH of the sample to between 10 and 14, adding a coloring agent to the sample capable of reacting with fructosamine to develop a color and, after a delay, taking a color measurement and comparing the resultant color with the color developed with said coloring agent with a standard fructosamine solution.

Claim 6

A method according to any preceding claim, characterised in that said p H level lies between 10.5 and 10.8.

Claim 7

A method according to any preceding claim, characterised in that said pH level is adjusted by adding a buffer to the sample.

Claim 9

The method according to any preceding claim, characterised in that the coloring agent is tetrazolium salt.

Claim 11

The method according to any preceding claim, characterised in that the interfering substances are eliminated by holding the sample at a temperature of 3 7 0 C or higher.

Claim 12

The method according to any preceding claim, characterised in that the reaction between the coloring agent and serum glucose is stopped by the addition of an acid.

Claim 13

The method according to any preceding claim, characterised in that the pH is lowered to below 5 to stop the reaction between the coloring agent and fructosamine.