Method of detecting the presence or absence of a clot in a liquid sample analyzer

1. A method of detecting a clot in a measurement chamber of a liquid sample analyzer, the liquid sample analyzer comprising one or more analyte sensors arranged for measuring a physical parameter of an analyte in a liquid sample in the measurement chamber, wherein detection is performed after conclusion of a rinsing procedure with a primary solution having a pre-determined primary composition with a primary concentration of the analyte, the method comprising:

a. removing the primary solution from the measurement chamber, and at least partly filling the measurement chamber with a secondary solution having a pre-determined secondary composition with a secondary concentration of the analyte, wherein the secondary concentration is different from the primary concentration;

b. obtaining an initial measurement result by at least one of the one or more analyte sensors;

c. flushing the measurement chamber with the secondary solution, and leaving the secondary solution in the measurement chamber;

d. after a time delay from obtaining the initial measurement result, obtaining a subsequent measurement result by at least one of the one or more analyte sensors;

e. comparing the initial and subsequent measurement results; and

f. determining the presence or absence of a clot in the measurement chamber based on the comparison of the initial and subsequent measurement results, wherein:

the determining the presence or absence of a clot in the measurement chamber based on the comparison of the initial and subsequent measurement results comprises comparing the difference between the initial and subsequent measurement results to a threshold; and

the presence of a clot is determined if the difference between the initial and subsequent measurement results is above a threshold, and/or the absence of a clot is determined if the difference between the initial and subsequent measurement results is below the threshold.

2. The method according to claim 1 , wherein the liquid sample analyzer system is a blood analyzer system.

3. The method according to claim 1 , wherein the measurement chamber comprises several analyte sensors for measuring different analytes.

4. The method according to claim 3 , wherein the analyte sensors are one or more of dedicated sensors for measuring partial pressures of gasses, concentrations of electrolytes, concentrations of metabolites, concentrations of nutritional and/or pharmaceutical substances, and pH.

5. The method according to claim 1 , wherein the analyte is one or more of Na + , K + , Ca 2+ , Mg 2+ , Cl − , glucose, lactate, urea, creatinine, CO 2 , and O 2 .

6. The method according to claim 5 , wherein at least one of the one or more analyte sensors is an electrochemical analyte sensor including an ion selective electrode.

7. The method according to claim 1 , wherein the one or more analyte sensors are selected from the group of electrochemical sensors and optical sensors.

8. The method according to claim 1 , wherein the concentrations of the analyte contained in the primary and secondary solutions differ by at least a factor of 2, at least a factor of 5, at least a factor of 10, at least a factor of 20, at least a factor of 50, or at least a factor of 100.

9. A method for verifying removal of a clot identified in a measurement chamber after completion of measures intended for removal of said clot, the measures of clot removal concluding with a rinsing procedure using a primary solution, the method comprising: performing the method according to claim 1 after the presence of a clot in the measurement chamber has been determined.

10. A liquid sample analyzer adapted for performing a method of clot detection according to claim 1 , the liquid sample analyzer comprising a measurement chamber with inlet and outlet ports for feeding and discharging a liquid sample to the measurement chamber, an analyte sensor facing the measurement chamber arranged for measuring a physical parameter of the analyte in a liquid sample in the measurement chamber, and a signal processor configured for receiving signals from the analyte sensor as an input, for performing a comparison of the initial and subsequent measurement results based on that input, and for determining presence or absence of a clot in the measurement chamber based on the comparison.

11. The liquid sample analyzer according to claim 10 , wherein the liquid sample analyzer is adapted for the measurement of blood parameters in whole blood samples.

12. A method of detecting a clot in a measurement chamber of a liquid sample analyzer, the liquid sample analyzer comprising one or more analyte sensors arranged for measuring a physical parameter of an analyte in a liquid sample in the measurement chamber, wherein detection is performed after conclusion of a rinsing procedure with a primary solution having a pre-determined primary composition with a primary concentration of the analyte, the method comprising:

a. removing the primary solution from the measurement chamber, and at least partly filling the measurement chamber with a secondary solution having a pre-determined secondary composition with a secondary concentration of the analyte, wherein the secondary concentration is different from the primary concentration;

b. obtaining an initial measurement result by at least one of the one or more analyte sensors;

c. flushing the measurement chamber with the secondary solution, and leaving the secondary solution in the measurement chamber;

d. after a time delay from obtaining the initial measurement result, obtaining a subsequent measurement result by at least one of the one or more analyte sensors;

e. comparing the initial and subsequent measurement results; and

f. determining the presence or absence of a clot in the measurement chamber based on the comparison of the initial and subsequent measurement results,

wherein obtaining the respective initial and/or corresponding subsequent measurement results includes developing the initial measurement result from a respective initial discrete measurement, measurement sequence and/or developing the subsequent measurement result from a corresponding discrete measurement, or subsequent measurement sequence.

13. The method according to claim 12 , wherein the initial measurement result is an average over the respective initial measurement sequence and/or wherein the subsequent measurement value is an average over the corresponding subsequent measurement sequence.

14. The method according to claim 12 , wherein the initial measurement result is an initial rate of change for the initial measurement sequence, and wherein the subsequent measurement value is a subsequent rate of change for the corresponding subsequent measurement sequence.

15. A method of detecting a clot in a measurement chamber of a liquid sample analyzer, the liquid sample analyzer comprising one or more analyte sensors arranged for measuring a physical parameter of an analyte in a liquid sample in the measurement chamber, wherein detection is performed after conclusion of a rinsing procedure with a primary solution having a pre-determined primary composition with a primary concentration of the analyte, the method comprising:

a. removing the primary solution from the measurement chamber, and at least partly filling the measurement chamber with a secondary solution having a pre-determined secondary composition with a secondary concentration of the analyte, wherein the secondary concentration is different from the primary concentration;

b. obtaining an initial measurement result by at least one of the one or more analyte sensors;

c. flushing the measurement chamber with the secondary solution, and leaving the secondary solution in the measurement chamber;

d. after a time delay from obtaining the initial measurement result, obtaining a subsequent measurement result by at least one of the one or more analyte sensors;

e. comparing the initial and subsequent measurement results; and

f. determining the presence or absence of a clot in the measurement chamber based on the comparison of the initial and subsequent measurement results,

wherein the presence or absence of a clot in the measurement chamber is determined by identifying a response to switching from a high analyte level in the primary solution to a low analyte level in the secondary solution or by identifying a response to switching from a low analyte level in the primary solution to a high analyte level in the secondary solution.