ANALYTICAL TEST CARTRIDGE; AND, METHODS
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.