Apparatus for analysis of a nucleic acid amplification reaction

An apparatus for determining a threshold time value in a nucleic acid amplification reaction, the apparatus comprising:

• a) a detection mechanism for measuring, at a plurality of different times during the amplification reaction, at least one signal whose intensity is related to the quantity of a nucleic acid sequence being amplified in the reaction;
• and
• b) a controller in communication with the detection mechanism, wherein the controller is programmed to perform the steps of:
• i) deriving a growth curve from the measurements of the signal;
• ii) calculating a derivative of the growth curve;
• iii) identifying a characteristic of the derivative;
• and
• iv) determining a time value associated with the characteristic of the derivative.

An apparatus for determining an unknown starting quantity of a target nucleic acid sequence in a test sample, the apparatus comprising:

• means for amplifying the unknown starting quantity of the target nucleic acid sequence in the test sample and for amplifying a plurality of known starting quantities of a calibration nucleic acid sequence in respective calibration samples;
• at least one detection mechanism for measuring, at a plurality of different times during amplification of the nucleic acid sequences, signals indicative of the quantities of the nucleic acid sequences being amplified in the test and calibration samples;
• and
• at least one controller in communication with the detection mechanism, wherein the controller is programmed to perform the steps of:
• a) determining a respective threshold value for each of the known starting quantities of the calibration nucleic acid sequence in the calibration samples and for the target nucleic acid sequence in the test sample, wherein each threshold value is determined for a nucleic acid sequence in a respective sample by:
• i) deriving a growth curve for the nucleic acid sequence from the measured signals;
• ii) calculating a derivative of the growth curve;
• iii) identifying a characteristic of the derivative;
• and
• iv) determining the threshold value associated with the characteristic of the derivative;
• b) deriving a calibration curve from the threshold values determined for the known starting quantities of the nucleic acid sequence in the calibration samples;
• and
• c) determining the starting quantity of the target nucleic acid sequence in the test sample using the calibration curve and the threshold value determined for the target sequence.

An apparatus for determining a threshold value in a nucleic acid amplification reaction, the apparatus comprising:

• a) at least one detection mechanism for measuring, at a plurality of different times during the amplification reaction, at least one signal whose intensity is related to the quantity of a nucleic acid sequence being amplified in the reaction;
• and
• b) a controller in communication with the detection mechanism, wherein the controller is programmed to perform the steps of:
• i) storing signal values defining a growth curve for the nucleic acid sequence, wherein the growth curve expresses signal intensity as a function of cycle number or as a function of time in the reaction;
• ii) determining a derivative of the growth curve, wherein the derivative is determined with respect to cycle number or time;
• and
• iii) calculating a cycle number or time value associated with a characteristic of the derivative.

An apparatus for determining an unknown starting quantity of a target nucleic acid sequence in a test sample, the apparatus comprising:

• means for amplifying the unknown starting quantity of the target nucleic acid sequence in the test sample and for amplifying a plurality of known starting quantities of a calibration nucleic acid sequence in respective calibration samples;
• at least one detection mechanism for measuring, at a plurality of different times during amplification of the nucleic acid sequences, signals indicative of the quantities of the nucleic acid sequences being amplified in the test and calibration samples;
• and
• at least one controller in communication with the detection mechanism, wherein the controller is programmed to perform the steps of:
• a) determining a respective threshold value for each of the known starting quantities of the calibration nucleic acid sequence in the calibration samples and for the target nucleic acid sequence in the test sample, wherein each threshold value is determined for a nucleic acid sequence in a respective sample by:
• 1) storing signal values defining a growth curve for the nucleic acid sequence, wherein the growth curve expresses signal intensity as a function of cycle number or as a function of time in the reaction;
• 2) determining a derivative of the growth curve, wherein the derivative is determined with respect to cycle number or time;
• and
• 3) calculating a cycle number or time value associated with a characteristic of the derivative;
• b) deriving a calibration curve from the threshold values determined for the known starting quantities of the calibration nucleic acid sequence in the calibration samples;
• and
• c) determining the starting quantity of the target nucleic acid sequence in the test sample using the calibration curve and the threshold value determined for the target sequence.