Analytical test cartridge; and, methods
View Patent ↗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 spins located off of and in fluid flow communication with the main flow channel; and, a titration cell in each spur separated from the main flow channel;
(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 cartridge 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 changer;
(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 mare 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 sensor located in the 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 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 located off of and in fluid flow communication with a single main flow channel, each spur leading to one or more of a plurality of titration cells containing sensors;
(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 cells; and
(c) calculating an amount of an 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.