High confidence in positive status determination
First Claim
1. A method comprising:
- (A) incubating, with an incubator, a culture disposed within a vessel during portions of a time interval between a first time point and a second time point, wherein the culture comprises a sample and a culture media;
(B) measuring, with a sensor, a biological state of the culture at a plurality of time points between the first time point and the second time point, wherein the biological state is one of CO2 concentration, O2 concentration, pH, a rate of change in CO2 concentration, a rate of change in O2 concentration, or a rate of change in pH;
(C) determining, with one or more processors, a plurality of rate transformation values, wherein each rate transformation value is derived from a different subset of the measurements of the biological state of the culture within a predetermined time interval;
(D) determining, with the one or more processors, a plurality of average relative transformation values, wherein each average relative transformation value is derived from a different subset of the rate transformation values;
(E) determining, with the one or more processors, that the culture contains a plurality of microorganisms when (i) at least one average relative transformation value exceeds a first threshold value or (ii) an extent of growth exhibited by the culture exceeds a second threshold value, wherein the extent of growth is derived from one or more of the measurements of the biological state of the culture; and
(F) processing the vessel to confirm the presence of the plurality of microorganisms after it is determined in step (E) that the culture contains a plurality of microorganisms.
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Accused Products
Abstract
Systems, methods, and apparatus for determining whether a culture in a vessel contains a plurality of microorganisms are provided. A normalization relative value is calculated for each respective measurement of a biological state of the culture between (i) the respective measurement and (ii) an initial biological state. For each fixed interval of time points, a derivative of the normalization relative values in the interval of time points is calculated, thereby forming a plurality of rate transformation values. For each set of rate transformation values in the plurality of rate transformation values, a measure of central tendency of the values in the set is computed, thereby forming a plurality of average relative transformation values. A determination whether the culture contains the microorganisms is made based on whether any calculated average relative transformation value exceeds a first threshold or whether an extent of growth exhibited by the culture exceeds a second threshold.
18 Citations
20 Claims
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1. A method comprising:
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(A) incubating, with an incubator, a culture disposed within a vessel during portions of a time interval between a first time point and a second time point, wherein the culture comprises a sample and a culture media; (B) measuring, with a sensor, a biological state of the culture at a plurality of time points between the first time point and the second time point, wherein the biological state is one of CO2 concentration, O2 concentration, pH, a rate of change in CO2 concentration, a rate of change in O2 concentration, or a rate of change in pH; (C) determining, with one or more processors, a plurality of rate transformation values, wherein each rate transformation value is derived from a different subset of the measurements of the biological state of the culture within a predetermined time interval; (D) determining, with the one or more processors, a plurality of average relative transformation values, wherein each average relative transformation value is derived from a different subset of the rate transformation values; (E) determining, with the one or more processors, that the culture contains a plurality of microorganisms when (i) at least one average relative transformation value exceeds a first threshold value or (ii) an extent of growth exhibited by the culture exceeds a second threshold value, wherein the extent of growth is derived from one or more of the measurements of the biological state of the culture; and (F) processing the vessel to confirm the presence of the plurality of microorganisms after it is determined in step (E) that the culture contains a plurality of microorganisms. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. An apparatus comprising:
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(A) one or more processors; (B) an incubator for incubating a culture disposed within a vessel during portions of a time interval between a first time point and a second time point, wherein the culture comprises a sample and a culture media; (C) a sensor for measuring a biological state of the culture at a plurality of time points between the first time point and the second time point, wherein the biological state is one of CO2 concentration, O2 concentration, pH, a rate of change in CO2 concentration, a rate of change in O2 concentration, or a rate of change in pH; and (D) a memory comprising; (1) a first threshold value; (2) a second threshold value; and (3) a culture determination module comprising; (a) electronically encoded instructions for determining a plurality of rate transformation values, wherein each rate transformation value is derived from a different subset of the measurements of the biological state of the culture within a predetermined time interval; (b) electronically encoded instructions for determining a plurality of average relative transformation values, wherein each average relative transformation value is derived from a different subset of the rate transformation values; and (c) electronically encoded instructions for determining that the culture contains a plurality of microorganisms when (i) at least one average relative transformation value exceeds the first threshold value or (ii) an extent of growth exhibited by the culture exceeds the second threshold value, wherein the extent of growth is derived from one or more of the measurements of the biological state of the culture; and (E) a user interface configured to notify a user that the vessel should be processed to confirm the presence of the plurality of microorganisms after it is determined that the culture contains a plurality of microorganisms. - View Dependent Claims (17, 18, 19, 20)
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Specification