Reference solution

• US 9,068,998 B2
• Filed: 06/17/2008
• Issued: 06/30/2015
• Est. Priority Date: 11/28/2003
• Status: Active Grant

• Current Assignee: Radiometer Medical ApS (Danaher Corporation)
• Original Assignee: Radiometer Medical ApS (Danaher Corporation)
• Inventors: Lunding, Gitte
• Primary Examiner(s): Weber, Jon P
• Assistant Examiner(s): Kosar, Aaron J
• Application Number:
  US12/140,892
• Publication Number:
  US 20080254542A1
• Time in Patent Office: 2,569 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: C12Q 1/001 Enzyme electrodes
• CPC Class Codes: C12Q 1/34 involving hydrolase
• CPC Class Codes: G01N 2333/986 acting on amide bonds in cyclic amides (3.5.2), e.g. beta-lactamase (penicillinase, 3.5.2.6), creatinine amidohydrolase (creatininase, EC 3.5.2.10), N-methylhydantoinase (3.5.2.6)
• CPC Class Codes: G01N 33/70 involving creatine or creatinine
• CPC Class Codes: G01N 33/96 involving blood or serum control standard
• CPC Class Codes: Y10T 436/10 Composition for standardization, calibration, simulation, stabilization, preparation or preservation; processes of use in preparation for chemical testing

Abstract

A reference solution is provided, which comprises, in a liquid phase, at least one of a first compound and a second compound which are mutually convertible into each other, and at least one catalyst, which catalyzes the conversion between the first compound and the second compound.

Claims

1. A method of calibrating a sensor for determining creatinine and creatine levels in a sample, the method comprising the steps of:

exposing the sensor to a reference solution comprising

creatinine and creatine in equilibrium in a liquid phase,

wherein the concentrations of the creatinine and the creatine in the solution are the equilibrium concentrations of the creatinine and the creatine; and

at least one catalyst dissolved in the solution, which catalyzes the conversion between the creatinine and the creatine,

determining the sensor response to the concentrations of the creatinine and the creatine in the reference solution; and

adjusting the sensor accordingly.

2. The method of claim 1, wherein the at least one catalyst is creatinine amidohydrolase.

3. The method of claim 1, further comprising preparing the reference solution by:

adding the creatinine and creatine to the liquid phase in a predetermined amount.

4. The method of claim 1, further comprising preparing the reference solution by:

adding to the liquid phase the creatinine and the creatine and the at least one catalyst; and

determining the equilibrium concentrations of the creatinine and the creatine at a selected temperature.

5. The method of claim 4, wherein the step of determining the equilibrium concentrations comprises:

measuring the total concentrations of the creatinine and the creatine; and

computing the equilibrium concentrations therefrom.

6. The method of claim 4, wherein the step of determining the equilibrium concentrations comprises:

measuring the concentrations of each of the creatinine and the creatine; and

computing the equilibrium concentrations therefrom.

7. The method of claim 4, wherein the step of determining the equilibrium concentrations comprises:

allowing establishment of the equilibrium concentrations of the creatinine and the creatine after addition of the at least one catalyst;

measuring the equilibrium concentration of one of the creatinine and the creatine; and

computing the equilibrium concentrations therefrom.

8. A method of performing quality control of a sensor comprising:

exposing the sensor to a reference solution comprising

creatinine and creatine in equilibrium in a liquid phase,

wherein the concentrations of the creatinine and the creatine in the solution are the equilibrium concentrations of the creatinine and the creatine; and

at least one catalyst dissolved in the solution which catalyzes the conversion between creatinine and creatine,

determining the sensor response to the concentrations of the creatinine and the creatine in the reference solution; and

adjusting the sensor accordingly

if the determined concentrations are outside a predetermined acceptance range.

9. The method of claim 8, wherein the at least one catalyst is creatinine amidohydrolase.

10. The method of claim 8, further comprising preparing the reference solution by adding the creatinine and creatine to the liquid phase in a predetermined amount.

11. The method of claim 8, further comprising preparing the reference solution by adding to the liquid phase the creatinine and the creatine and the at least one catalyst;

and determining the equilibrium concentrations of the creatinine and the creatine at a selected temperature.

12. The method of claim 11, wherein the step of determining the equilibrium concentrations comprises:

measuring the total concentrations of the creatinine and the creatine; and

computing the equilibrium concentrations therefrom.

13. The method of claim 11, wherein the step of determining the equilibrium concentrations comprises:

measuring the concentrations of each of the creatinine and the creatine; and

computing the equilibrium concentrations therefrom.

14. The method of claim 11, wherein the step of determining the equilibrium concentrations comprises:

allowing establishment of the equilibrium concentrations of the creatinine and the creatine after addition of the at least one catalyst;

measuring the equilibrium concentration of one of the creatinine and the creatine; and

computing the equilibrium concentrations therefrom.