SENSITIVITY AND THE DYNAMIC RANGE OF PHOTOMETRIC ASSAYS BY GENERATING MULTIPLE CALIBRATION CURVES

• US 20150046114A1
• Filed: 10/27/2014
• Published: 02/12/2015
• Est. Priority Date: 04/26/2012
• Status: Abandoned Application

• Current Assignee: Roche Diagnostics Operations Incorporated (Roche Holding AG)
• Original Assignee: Roche Diagnostics Operations Incorporated (Roche Holding AG)
• Inventors: Lopez-Calle, Eloisa, Oranth, Norbert, Brueckner, Thornsten, Roedl, Josef
• Application Number:
  US14/524,633
• Publication Number:
  US 20150046114A1
• Time in Patent Office: Days
• US Class Current: 702/104
• CPC Class Codes: G01D 18/00 Testing or calibrating apparatus or arrangements provided for in groups G01D1/00 - G01D15/00
• CPC Class Codes: G01N 2021/825 Agglutination
• CPC Class Codes: G01N 21/274 Calibration, base line adjustment, drift correction
• CPC Class Codes: G01N 21/63 optically excited
• CPC Class Codes: G01N 21/78 producing a change of colour
• CPC Class Codes: G01N 21/82 producing a precipitate or turbidity
• CPC Class Codes: G01N 33/52 Use of compounds or compositions for colorimetric, spectrophotometric or fluorometric investigation, e.g. use of reagent paper and including single- and multilayer analytical elements immunological elements G01N33/54386; involving labelled immunochemicals G01N33/58; for haemoglobin or occult blood G01N33/72
• CPC Class Codes: G01N 33/54313 the carrier being characterised by its particulate form
• CPC Class Codes: G01N 33/54346 Nanoparticles
• CPC Class Codes: G01N 33/54393 Improving reaction conditions or stability, e.g. by coating or irradiation of surface, by reduction of non-specific binding, by promotion of specific binding
• CPC Class Codes: G01N 33/573 for enzymes or isoenzymes
• CPC Class Codes: G01N 33/6827 Total protein determination, e.g. albumin in urine
• CPC Class Codes: G01N 33/92 involving lipids, e.g. cholesterol , lipoproteins, or their receptors steroid hormones G01N33/743
• CPC Class Codes: G16B 20/00 ICT specially adapted for functional genomics or proteomics, e.g. genotype-phenotype associations
• CPC Class Codes: G16H 50/30 for calculating health indices; for individual health risk assessment
• CPC Class Codes: Y02A 90/10 Information and communication technologies [ICT] supporting adaptation to climate change, e.g. for weather forecasting or climate simulation

Abstract

A method for determining the amount of a specific analyte by photometric assays, wherein the specific analyte in a sample reacts with an analyte specific reaction partner in a reaction mixture. At least two calibration curves are generated, the first calibration curve recorded at a first wavelength is optimized for low concentrations of the specific analyte thereby maximizing the lower detection limit and, the second calibration curve recorded at a second wavelength is optimized for high concentrations of the specific analyte thereby maximizing the upper detection limit. The optimized lower detection limit and the optimized upper detection limit results in an extended dynamic range.

Claims

1. A method for determining the amount of a specific analyte by photometric assays, wherein the specific analyte in a sample reacts with an analyte specific reaction partner in a reaction mixture, comprising the steps of:

a) generating at least two calibration curves, wherein

the first calibration curve recorded at a first wavelength is optimized for low concentrations of the specific analyte thereby maximizing the lower detection limit, and

the second calibration curve recorded at a second wavelength is optimized for high concentrations of the specific analyte thereby maximizing the upper detection limit;

b) measuring simultaneously the optical signal for the specific analyte of a sample to be determined in the reaction mixture at least at the first and second wavelengths;

c) selecting either the first or the second calibration curve for quantification of the specific analyte, by the following criteria;

for increasing calibration curves;

if the optical signal of the first and/or the second wavelength is lower than a corresponding predetermined threshold value, the concentration of the analyte is determined by the use of the first calibration curve recorded at the first wavelength;

if the optical signal of the first and/or the second wavelength exceeds a corresponding predetermined threshold value, the concentration of the analyte is determined by the use of the second calibration curve recorded at the second wavelength;

for decreasing calibration curves;

if the optical signal of the first and/or the second wavelength is lower than a corresponding predetermined threshold value, the concentration of the analyte is determined by the use of the second calibration curve recorded at the second wavelength;

if the optical signal of the first and/or the second wavelength exceeds a corresponding predetermined threshold value, the concentration of the analyte is determined by the use of the first calibration curve recorded at the first wavelength, and

d) quantifying the amount of the specific analyte by comparison with the selected calibration curve.

2. The method according to claim 1, wherein in turbidimetric and nephelometric immunoassays the specific analyte is quantified from the change in the turbidity of the reaction mixture based on the agglutination of the specific analyte and an analyte specific binding partner.

3. The method according to claim 1, wherein in colorimetric assays the specific analyte is quantified with the aid of a color reagent.

4. The method according to claim 1, wherein the first calibration curve is recorded at a first wavelength and at a first reaction time.

5. The method according to claim 1, wherein the second calibration curve is recorded at a second wavelength and of a second reaction time.

6. The method according to claim 1, wherein the simultaneous measurement of the optical signal for the specific analyte of a sample to be determined in the reaction mixture is performed at least at the first and second wavelengths over the complete reaction time.

7. The method according to claim 1, wherein the measurement results are stored in a data management system of the instrument platform.

8. The method according to claim 1, wherein further wavelengths are determined as a blank value for the correction of interferences and compensation of photometric noise.

9. The method according to claim 1, wherein at least two calibration curves are generated that are recorded at the same wavelengths and at different reaction times.

10. The method according to claim 1, wherein the analyte specific reaction partner further comprises binding proteins, antigens, antigen fragments, antibodies, antibody fragments, nucleic acids, receptors and particle enhanced binding partners, enzymes, substrates or specific chemical reagents leading to a color change or to a turbidity change in the presence of an analyte.

12. A computer-implemented method of determining the optimal wavelength, reaction time and threshold according to claim 1, comprising the steps of:

a) receiving a dataset representing the absorbance values of the samples recorded at multiple wavelengths over the complete reaction time simultaneously available on an analyzer, wherein said dataset includes a plurality of data points for;

standards for the calibration,

a blank sample for determination of LDL,

at least 2 samples for the determination of the precision, and/or

dilution series;

b) setting the threshold values at a concentration where the calibration curves change from the first to the second calibration curve, by using for lower concentrations the first calibration curve for the analyte quantification and by using for higher concentrations the second calibration curve for the analyte quantification; and

c) determining the first and second wavelength as well as the first and the second reaction time, analyzing the kinetic curves and selecting the optimal set up for the first calibration curve and the second calibration curve.

13. A computer readable medium including code controlling a processor to determine the optimal wavelength, reaction time and threshold according to one of the preceding claims, the code including instructions to:

a) receiving a dataset representing the absorbance values of the samples recorded at multiple wavelengths over the complete reaction time simultaneously available on an analyzer, wherein said dataset includes a plurality of data points for;

standards for the calibration,

a blank sample for determination of LDL,

at least 2 samples for the determination of the precision, and/or

dilution series;

b) setting the threshold values at a concentration where the calibration curves change from the first to the second calibration curve, by using for lower concentrations the first calibration curve for the analyte quantification and by using for higher concentrations the second calibration curve for the analyte quantification; and

c) determining the first and second wavelength as well as the first and the second reaction time, analyzing the kinetic curves and selecting the optimal set up for the first calibration curve and the second calibration curve.

11. A method for increasing the sensitivity and/or dynamic range of photometric assays, wherein the specific analyte in a sample reacts with an analyte specific reaction partner in a reaction mixture, comprising the steps of:

a) generating at least two calibration curves, wherein

the first calibration curve recorded at a first wavelength is optimized for low concentrations of the specific analyte thereby maximizing the lower detection limit, and

the second calibration curve recorded at a second wavelength is optimized for high concentrations of the specific analyte thereby maximizing the upper detection limit;

b) measuring simultaneously the optical signal for the specific analyte of a sample to be determined in the reaction mixture at least at the first and second wavelengths;

c) selecting either the first or the second calibration curve for quantification of the specific analyte, by the following criteria;

for increasing calibration curves;

if the optical signal of the first and/or the second wavelength is lower than a corresponding predetermined threshold value, the concentration of the analyte is determined by the use of the first calibration curve recorded at the first wavelength,

if the optical signal of the first and/or the second wavelength exceeds a corresponding predetermined threshold value, the concentration of the analyte is determined by the use of the second calibration curve recorded at the second wavelength;

for decreasing calibration curves;

if the optical signal of the first and/or the second wavelength is lower than a corresponding predetermined threshold value, the concentration of the analyte is determined by the use of the second calibration curve recorded at the second wavelength,

if the optical signal of the first and/or the second wavelength exceeds a corresponding predetermined threshold value, the concentration of the analyte is determined by the use of the first calibration curve recorded at the first wavelength; and

d) quantifying the amount of the specific analyte by comparison with the selected calibration curve.