Analytical test cartridge; and, methods

Abstract

An analytical test cartridge is provided. The analytical test cartridge can be used for medical analyses of liquid samples removed from a patient, for example blood. The analytical test cartridge is configured to provide for titration experiments. An example of a titration experiment that can be performed with the arrangement, is titration of heparin with protamine. Methods of assembly and use are provided.

1 . A sample analysis cartridge comprising:
 (a) a liquid sample inlet;   (b) a main flow channel in fluid flow communication with the inlet;   (c) a titration cell arrangement including: at least two titration spurs in fluid flow communication with the main flow channel; and, a titration cell in each spur;   (d) a titration sensor arrangement including a sensor positioned in each titration cell in the titration cell arrangement; and   (e) a titration agent positioned in each titration cell of the titration cell arrangement, with a different amount of titration agent in at least two of the titration cells.   
     
     
         2 . A sample analysis cartridge according to  claim 1  including:
 (a) an electrical conductor arrangement positioned to provide operational electrical communication from the sensor arrangement to an analytical measurement device, when the cartridge is operably connected to the analytical measurement device.   
     
     
         3 . A sample analysis cartridge according to  claim 1  including:
 (a) a secondary flow channel providing fluid flow communication between the main flow channel and the titration cell arrangement.   
     
     
         4 . A sample analysis cartridges according to  claim 1  wherein:
 (a) the titration cell arrangement includes at least four titration spurs, each of which includes a titration cell; and   (b) a different amount of titration agent is positioned in at least four of the titration cells.   
     
     
         5 . A sample analysis cartridge according to  claim 1  including:
 (a) a spur waste chamber;
 (i) each titration spur being configured for fluid flow communication from the main flow channel, eventually through a selected titration cell and to the spur waste chamber. 
   
     
     
         6 . A sample analysis cartridge according to  claim 1  wherein:
 (a) each titration spur is a capillary spur.   
     
     
         7 . A sample analysis cartridge according to  claim 1  wherein:
 (a) a selected set of titration cells, including more than one of said titration cells, comprises a selected analyte titration set of titration cells;
 (i) each cell in the selected analyte titration set of titration cells includes a titrating agent for a selected analyte; and 
 (ii) an amount of titrating agent for the selected analyte in selected ones of the capillary spurs in the selected analyte titration set, differs adequately to generate a selected analyte titration calculation based upon operation of said electrochemical sensor arrangement. 
   
     
     
         8 . A sample analysis cartridge according to  claim 7  wherein:
 (a) the titrating agent for the selected analyte is a titrating agent for heparin.   
     
     
         9 . A sample analysis cartridge according to  claim 8  wherein:
 (a) the titrating agent is protamine.   
     
     
         10 . A sample analysis cartridge according to  claim 9  wherein:
 (a) each capillary spur of the selected analyte titration set defines a titration cell volume within 5% of a selected titration cell volume.   
     
     
         11 . A sample analysis cartridge according to  claim 1  comprising:
 (a) a base structure defining a cartridge perimeter area of no more than 100 sq. cm.   
     
     
         12 . A sample analysis cartridge according to  claim 11  having:
 (a) a total sample volume in the main flow channel and the titration spurs of no more than 100 microliters.   
     
     
         13 . A sample analysis cartridge according to  claim 12  having:
 (a) a titration cell volume, of each titration cell, of no more than 2.5 μl.   
     
     
         14 . A sample analysis cartridge according to  claim 12  including:
 (a) a single reference electrode, for all sensors located in titration cells; the single reference electrode being positioned in the main flow channel.   
     
     
         15 . A sample analysis cartridge according to  claim 14  including:
 (a) at least one analytical sensor electrode positioned in the main flow channel.   
     
     
         16 . A sample analysis cartridge according to  claim 12  including:
 (a) a main flow channel waste reservoir;
 (i) said main flow conduit being positioned in fluid flow communication between said liquid sample injection port and said main flow channel waste reservoir. 
   
     
     
         17 . A method of defining an analyte presence in a liquid sample; said method including steps of:
 (a) directing a liquid sample into a plurality of spurs in fluid flow communication with a single main flow channel;   (b) titrating at least one of a selected analyte and a selected reagent in the liquid sample to a different degree in selected ones of the plurality of the spurs; and,   (c) calculating an amount of a analyte in the liquid sample based on a titration analysis determined by the step of titrating.   
     
     
         18 . A method according to  claim 17  wherein:
 (a) said step of titrating comprises titrating heparin in a blood sample.   
     
     
         19 . A method according to  claim 17  wherein:
 (a) said step of directing comprises directing a liquid sample into an analytical sample cartridge having a total perimeter area of no more than 100 sq. cm.   
     
     
         20 . A method according to  claim 19  wherein:
 (a) said step of calculating comprises calculating on a basis of titration measurements taken in at least six different cells at different amounts of titration.   
     
     
         21 . A method according to  claim 17  wherein:
 (a) said step of titrating comprises titrating heparin, in blood, with protamine.