Measuring Range Extension of Chromatographic Rapid Tests

Abstract

A method for the quantitative determination of an analyte in a sample is provided comprising: (a) providing an analyte-specific substance which is able to undergo a reaction which generates a detectable signal when it is contacted with an analyte; (b) providing at least two calibration graphs which have been generated by reacting in each case the same analyte-specific substance with different amounts of in each case the same test analyte for in each case a predetermined reaction time; (c) contacting the analyte-specific substance with a sample which contains the analyte to be detected; (d) measuring the signal at a first predetermined reaction time for which a first calibration graph according to (b) is provided; (e) checking whether the signal measured according to (d) enables quantitative determination of the analyte with a desired accuracy; (f) (i) quantitatively determining the analyte on the basis of the signal measured according to (d) if the desired accuracy is reached, or (ii) measuring the signal at a second predetermined reaction time for which a second calibration graph according to (b) is provided; (g) checking whether the signal measured according to (f(ii)) enables a quantitative determination of the analyte with a desired accuracy; and (h) (i) quantitatively determining the analyte on the basis of the signal measured according to f(ii) if the desired accuracy is reached, or (ii) continuing the determination at at least one further predetermined reaction time (corresponding to (f)(ii), (g), (h)(i)).

1 . A method for the quantitative determination of an analyte in a sample, comprising: 
 (a) providing an analyte-specific substance which is able to undergo a reaction which generates a detectable signal when it is contacted with an analyte,    (b) providing at least two calibration graphs which have been generated by reacting in each case the same analyte-specific substance with different amounts of in each case the same test analyte for in each case a predetermined reaction time,    (c) contacting the analyte-specific substance with a sample which contains the analyte to be detected,    (d) measuring the signal at a first predetermined reaction time for which a first calibration graph according to (b) is provided,    (e) checking whether the signal measured according to (d) enables a quantitative determination of the analyte with a desired accuracy,    (f) (i) quantitatively determining the analyte on the basis of the signal measured according to (d) if the desired accuracy is reached,     or     (ii) measuring the signal at a second predetermined reaction time for which a second calibration graph according to (b) is provided,    (g) checking whether the signal measured according to (f(ii)) enables a quantitative determination of the analyte with a desired accuracy, and    (h) (i) quantitatively determining the analyte on the basis of the signal measured according to f(ii) if the desired accuracy is reached     or     (ii) continuing the determination at at least one further predetermined reaction time (corresponding to (f)(ii), (g), (h)(i)).    
     
     
         2 . The method according to  claim 1 , wherein the accuracy of the quantitative determination of the analyte is checked using the slope of the calibration graphs.  
     
     
         3 . The method according to  claim 1 , wherein the test analyte and the analyte to be determined quantitatively are identical.  
     
     
         4 . The method according to  claim 1 , wherein two or three calibration graphs are determined.  
     
     
         5 . The method according to  claim 1 , wherein a support is used to provide the analyte-specific substance.  
     
     
         6 . The method according to  claim 5 , wherein said support is a test strip.  
     
     
         7 . The method according to  claim 1 , wherein the limits of the measuring range for the analyte to be determined are extended by a factor of about 2 to about 5.  
     
     
         8 . The method according to  claim 1 , wherein the limits of the measuring range for the analyte to be determined are extended by a factor greater than about 3.  
     
     
         9 . The method according to  claim 1 , wherein said sample is derived from a body fluid.  
     
     
         10 . The method according to  claim 9 , wherein the body fluid is selected from blood, plasma, serum, saliva, urine and combinations thereof.  
     
     
         11 . The method according to  claim 1  further comprising qualitatively and/or quantitatively determining one or more additional analytes at the same time as the analyte to be determined quantitatively.  
     
     
         12 . The method according to  claim 1 , wherein the analyte is selected from nucleic acids, lipids, carbohydrates, and proteins.  
     
     
         13 . The method according to  claim 1 , wherein the analyte is selected from DNA, RNA, antibodies, antigens, metabolic products, hormones, viruses, microorganisms, cells, cardio-specific markers, neurohormonal markets, ischaemic markers and muscle-specific markers.  
     
     
         14 . The method according to  claim 1 , wherein at least one cardiospecific marker selected from troponin T, myoglobin, D-dimer and NT-proBNP is determined.  
     
     
         15 . The method according to  claim 1 , wherein the analyte-specific substance is selected from antibodies, receptors that can bind to the analyte, antigens, lectin, nucleic acids and nucleic acid analogues.  
     
     
         16 . The method according to  claim 1 , wherein the analyte-specific substance is coupled to a detection reagent.  
     
     
         17 . The method according to  claim 1 , wherein the reaction between analyte and analyte-specific substance is an immunological reaction.  
     
     
         18 . The method according to  claim 1 , wherein the quantitative determination is carried out by optical methods.  
     
     
         19 . The method according to  claim 18 , wherein the optical method is selected from reflection photometric or fluorimetric detection or electrochemiluminescence.  
     
     
         20 . The method according to  claim 1 , wherein the method proceeds in an automated fashion.  
     
     
         21 . A method for the quantitative determination of an analyte in a sample comprising: 
 (a) providing an analyte-specific substance which is able to undergo a reaction which generates a detectable signal when it is contacted with an analyte,    (b) providing at least two calibration graphs which have been generated by reacting in each case the same analyte-specific substance with different amounts of in each case the same test analyte for in each case a predetermined reaction time,    (c) contacting the analyte-specific substance with a sample which contains the analyte to be detected,    (d) measuring a first signal at a first predetermined reaction time for which a first calibration graph according to (b) is provided,    (e) measuring a second signal at a second predetermined reaction time for which a second calibration graph according to (b) is provided,    (f) optionally measuring a further signal,    (g) checking which of the signals measured according to (d), (e) or (f) enables a sufficient accuracy for the quantitative determination of the analyte, and    (h) quantitatively determining the analyte on the basis of the signal which enables an adequate accuracy.