Apparatuses for detecting degraded test chemicals in analytical test elements

Abstract

Analytical apparatuses are disclosed for detecting at least one analyte in a sample, where in an analyte measurement at least an electrical or optical property changeable by presence of the analyte at least one test chemical of a test element is recorded, and where the analytical apparatus also can perform at least one quality measurement on the at least one test chemical such as an intrinsic luminescence, which is recorded and from the intrinsic luminescence a conclusion is drawn on a quality of the test chemical and thus the test element. Methods also are disclosed for detecting at least one analyte in a sample that include a quality measurement of the at least one test chemical of the test strip.

The invention claimed is: 
     
         1 . An analytical apparatus for measuring an analyte concentration, the apparatus comprising:
 at least one test element for measuring the analyte concentration, wherein the at least one test element has at least one test field, the at least one test field being an area in which at least one cohesive layer of at least one test chemical is applied to a carrier element or os incorporated into the carrier element;   at least one quality measurement device configured to measure at least one intrinsic luminescence of the at least one test chemical before a fluid sample is applied to the at least one test field of the at least one test element;   at least one analyte measurement device configured to measure the analyte concentration after the fluid sample is applied to the at least one test field of the at least one test element; and   at least one evaluation device configured to record the analyte concentration and to record the at least one intrinsic luminescence in at least a first intrinsic luminescence or at least a first intrinsic luminescence spectrum in a first wavelength interval and at least a second intrinsic luminescence or at least a second intrinsic luminescence spectrum in at least a second wavelength interval, wherein the at least one evaluation device is further configured to determine a quality of the at least one test chemical, wherein the quality comprises at least one item of quality information that indicates degrading or aging of the at least one test chemical.   
     
     
         2 . The analytical apparatus of  claim 1 , wherein the at least one analyte measurement device is an optical analyte measurement device or an electrical analyte measurement device. 
     
     
         3 . The analytical apparatus of  claim 2 , wherein the optical analyte measurement device comprises at least one light source and at least one optical analyte detector. 
     
     
         4 . The analytical apparatus of  claim 3 , wherein the at least one light source emits light in a range from about 340 nm to about 380 nm. 
     
     
         5 . The analytical apparatus of  claim 1 , wherein the at least one quality measurement device is an optical quality detector. 
     
     
         6 . The analytical apparatus of  claim 5 , wherein the optical quality detector comprises at least one light source and at least one optical quality detector. 
     
     
         7 . The analytical apparatus of  claim 6 , wherein the at least one light source emits light in a range from about 340 nm to about 380 nm. 
     
     
         8 . The analytical apparatus of  claim 1 , wherein the at least one evaluation device comprises a microprocessor configured to calculate at least a quality index from the at least one intrinsic luminescence in the at least two different wavelength regions or a linear combination of the intrinsic luminescences. 
     
     
         9 . The analytical apparatus of  claim 1 , wherein the at least one evaluation device comprises:
 a data store having at least one predetermined threshold value for the at least one intrinsic luminescence; and   a microprocessor configured to compare the at least one recorded intrinsic luminescence to the at least one predetermined threshold and not perform the analyte concentration measurement if the at least one recorded intrinsic luminescence is above the at least one predetermined threshold.   
     
     
         10 . The analytical apparatus of  claim 1 , wherein the at least one evaluation device comprises:
 a data store having at least one predetermined threshold value for the at least one intrinsic luminescence; and   a microprocessor configured to compare the at least one recorded intrinsic luminescence to the at least one predetermined threshold and discard the analyte concentration if the at least one recorded intrinsic luminescence is above the at least one predetermined threshold.   
     
     
         11 . The analytical apparatus of  claim 1 , wherein the at least one evaluation device comprises:
 a data store having at least one correction function for the at least one intrinsic luminescence; and   a microprocessor configured to correct or compensate the analyte concentration based upon the at least one intrinsic luminescence.   
     
     
         12 . The analytical apparatus of  claim 1 , wherein the at least one evaluation device records the at least one intrinsic luminescence at a wavelength range from about 380 nm to about 420 nm. 
     
     
         13 . The analytical apparatus of  claim 1 , wherein the at least one evaluation device records the at least one intrinsic luminescence at a wavelength range from about 420 nm to about 650 nm. 
     
     
         14 . The analytical apparatus of  claim 1 , wherein the at least one test chemical comprises an oxidase or a dehydrogenase. 
     
     
         15 . The analytical apparatus of  claim 14 , wherein the dehydrogenase is selected from the group consisting of glucose 6-phosphate dehydrogenase (EC 1.1.1.49), NAD-dependent cholesterol dehydrogenase (EC 1.1.1.62), FAD-dependent glucose dehydrogenase (EC 1.1.99.10) and PQQ-dependent glucose dehydrogenase (EC 1.1.5.2). 
     
     
         16 . The analytical apparatus of  claim 1 , wherein the at least one test chemical is L-amino acid dehydrogenase (E.C.1.4.1.5). 
     
     
         17 . The analytical apparatus of  claim 1 , wherein the at least one test chemical is an aspartate aminotransferase or an alanine aminotransferase.