Device and method for determining analyte levels

• US 7,974,672 B2
• Filed: 04/19/2010
• Issued: 07/05/2011
• Est. Priority Date: 03/04/1997
• Status: Expired due to Fees

• Current Assignee: DexCom Incorporated
• Original Assignee: DexCom Incorporated
• Inventors: Shults, Mark C., Updike, Stuart J., Rhodes, Rathbun K.
• Primary Examiner(s): Mallari; Patricia C
• Assistant Examiner(s): D'Angelo; Michael
• Application Number:
  US12/763,013
• Publication Number:
  US 20100204555A1
• Time in Patent Office: 442 Days
• Field of Search: 600345-347, 600/365
• US Class Current: 600/345
• CPC Class Codes: A61B 5/0004 characterised by the type of physiological signal transmitted
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/14865 invasive, e.g. introduced into the body by a catheter or needle or using implanted sensors
• CPC Class Codes: A61B 5/1495 Calibrating or testing of in-vivo probes
• CPC Class Codes: C12Q 1/006 for glucose

Abstract

Devices and methods for determining analyte levels are described. The devices and methods allow for the implantation of analyte-monitoring devices, such as glucose monitoring devices, that result in the delivery of a dependable flow of blood to deliver sample to the implanted device. The devices comprise a unique microarchitectural arrangement in the sensor region that allows accurate data to be obtained over long periods of time.

Claims

1. A system for processing sensor data from a continuous analyte sensor, comprising:

a sensor comprising an electrode configured for implantation in a subcutaneous tissue of a host, wherein the sensor is configured to continuously measure an analyte concentration, whereby sensor data associated with the subcutaneous analyte concentration is generated; and

electronic circuitry operably connected to the sensor and configured to perform an initial in vivo calibration of the sensor data using pre-implant calibration information;

wherein the system is configured to provide a substantially accurate measurement of the analyte concentration in the host such that at least 95% of calibrated sensor analyte values as determined by analysis of blood obtained during a useful life of the sensor are within 25% of actual analyte values.

2. The system of claim 1, wherein the pre-implant calibration information comprises a value obtained from an in vitro calibration.

3. The system of claim 2, wherein the in vitro calibration is obtained by measuring at least two different analyte concentrations.

4. The system of claim 2, wherein the in vitro calibration is obtained at about 37 degrees C.

5. The system of claim 1, wherein the electronic circuitry is further configured to perform periodic recalibration after an initial calibration time period, and wherein the periodic recalibration is based on a reference analyte value.

6. The system of claim 5, wherein the reference analyte value is correlated with a time-shifted sensor data value.

7. The system of claim 5, wherein the recalibration comprises an adjustment in sensor gain.

8. The system of claim 1, wherein the useful life is greater than about 3 days.

9. The system of claim 1, wherein the useful life is greater than about 5 days.

10. The system of claim 1, wherein the useful life is greater than about 7 days.

11. The system of claim 1, wherein the useful life is about one month.

12. The system of claim 1, wherein the analyte is glucose, and wherein the sensor is configured to respond substantially linearly to changes in glucose concentration at glucose concentrations ranging from about 40 mg/dL to about 500 mg/dL.

13. The system of claim 1, wherein the system is configured to provide a stable sensor offset during a period of time of continuous measurement of an analyte concentration in the host.

14. The system of claim 1, wherein the electronic circuitry is configured to determine trends in analyte concentration.

15. The system of claim 1, wherein the electronic circuitry is configured to physically couple the sensor.

16. The system of claim 1, wherein the electronic circuitry is configured to couple, via radio telemetry, to the sensor.

17. The system of claim 1, wherein the analyte is glucose.

18. The system of claim 1, wherein the electronic circuitry is configured to perform recalibration during the useful life of the sensor.

19. The system of claim 18, wherein the electronic circuitry is configured to perform recalibration periodically throughout the useful life of the sensor.

20. The method of claim 18, wherein recalibration is based on reference data.

21. The system of claim 1, wherein the electronic circuitry is configured to use the pre-implant calibration information for calibration of the sensor data throughout the useful life of the sensor.

22. The system of claim 1, wherein the electronic circuitry is configured to perform a calibration check during the useful life of the sensor.

23. The system of claim 1, wherein the sensor is configured to maintain a stability of calibration within 10% for one week.

24. A method for processing sensor data from a continuous analyte sensor, comprising:

receiving sensor data from an analyte sensor, the sensor data indicative of an analyte concentration in a host;

calibrating the sensor data, after insertion of the analyte sensor in the host, by using pre-implant calibration information;

and

generating, using an electronic system, a substantially accurate measurement of the analyte concentration, such that at least 95% of calibrated sensor analyte values are within 25% of actual analyte values as determined by analysis of blood obtained during a useful life of the sensor.

25. The method of claim 24, wherein the pre-implant calibration information comprises a value obtained from an in vitro calibration.

26. The method of claim 25, wherein the in vitro calibration is obtained by measuring at least two different analyte concentrations.

27. The method of claim 25, wherein the in vitro calibration is obtained at about 37 degrees C.

28. The method of claim 24, further comprising periodically recalibrating the sensor data after an initial calibration time period, wherein the periodically recalibrating is based on a reference analyte value.

29. The method of claim 28, wherein the reference analyte value is correlated with a time-shifted sensor data value.

30. The method of claim 28, wherein the periodically recalibrating comprises adjusting a sensor gain.

31. The method of claim 24, wherein the useful life is greater than about 3 days.

32. The method of claim 24, wherein the useful life is greater than about 5 days.

33. The method of claim 24, wherein the useful life is greater than about 7 days.

34. The method of claim 24, wherein the useful life initial calibration time period is about one month.

35. The method of claim 24, wherein the analyte is glucose, and wherein the sensor is configured to respond substantially linearly to changes in glucose concentration at glucose concentrations ranging from about 40 mg/dL to about 500 mg/dL.

36. The method of claim 24, further comprising maintaining a stable sensor offset during a period of time of continuous measurement of an analyte concentration in the host.

37. The method of claim 24, further comprising determining trends in analyte concentration.

38. The method of claim 24, wherein the analyte is glucose.

39. The method of claim 24, further comprising recalibrating sensor data during the useful life of the sensor.

40. The method of claim 39, wherein the recalibrating is performed periodically throughout the useful life of the sensor.

41. The method of claim 39, wherein the recalibrating is based on reference data.

42. The method of claim 24, wherein calibration of the sensor data comprises using the pre-implant calibration information throughout the useful life of the sensor.

43. The method of claim 24, further comprising checking the calibration during the useful life of the sensor.

44. A system for processing sensor data from a continuous analyte sensor, comprising:

a sensor comprising an electrode configured for implantation in a subcutaneous tissue of a host, wherein the sensor is configured to continuously measure an analyte concentration, whereby sensor data associated with the subcutaneous analyte concentration is generated; and

electronic circuitry operably connected to the sensor and configured to perform an initial in vivo calibration of the sensor data using only pre-implant calibration information;

wherein the system is configured to provide a substantially accurate measurement of the analyte concentration in the host such that at least 95% of calibrated sensor analyte values as determined by analysis of blood obtained during a useful life of the sensor are within 25% of actual analyte values.

45. The system of claim 44, wherein the pre-implant calibration information comprises a value obtained from an in vitro calibration.

46. The system of claim 45, wherein the in vitro calibration is obtained by measuring at least two different analyte concentrations.

47. The system of claim 45, wherein the in vitro calibration is obtained at about 37 degrees C.

48. The system of claim 44, wherein the electronic circuitry is further configured to perform periodic recalibration after an initial calibration time period, and wherein the periodic recalibration is based on a reference analyte value.

49. The system of claim 48, wherein the reference analyte value is correlated with a time-shifted sensor data value.

50. The system of claim 48, wherein the recalibration comprises an adjustment in sensor gain.

51. The system of claim 44, wherein the useful life is greater than about 3 days.

52. The system of claim 44, wherein the useful life is greater than about 5 days.

53. The system of claim 44, wherein the useful life is greater than about 7 days.

54. The system of claim 44, wherein the useful life is about one month.

55. The system of claim 44, wherein the analyte is glucose, and wherein the sensor is configured to respond substantially linearly to changes in glucose concentration at glucose concentrations ranging from about 40 mg/dL to about 500 mg/dL.

56. The system of claim 44, wherein the system is configured to provide a stable sensor offset during a period of time of continuous measurement of an analyte concentration in the host.

57. The system of claim 44, wherein the electronic circuitry is configured to determine trends in analyte concentration.

58. The system of claim 44, wherein the electronic circuitry is configured to physically couple the sensor.

59. The system of claim 44, wherein the electronic circuitry is configured to couple, via radio telemetry, to the sensor.

60. The system of claim 44, wherein the analyte is glucose.

61. The system of claim 44, wherein the electronic circuitry is configured to perform recalibration during the useful life of the sensor.

62. The system of claim 61, wherein the electronic circuitry is configured to perform the recalibration periodically throughout the useful life of the sensor.

63. The method of claim 61, wherein recalibration is based on reference data.

64. The system of claim 44, wherein the electronic circuitry is configured to use the pre-implant calibration information for calibration of the sensor data throughout the useful life of the sensor.

65. The system of claim 44, wherein the electronic circuitry is configured to perform a calibration check during the useful life of the sensor.

66. The system of claim 44, wherein the sensor is configured to maintain a stability of calibration within 10% for one week.

67. A method for processing sensor data from a continuous analyte sensor, comprising:

receiving sensor data from an analyte sensor, the sensor data indicative of an analyte concentration in a host;

calibrating the sensor data, after insertion of the analyte sensor in the host, by using only pre-implant calibration information; and

generating, using an electronic system, a substantially accurate measurement of the analyte concentration, such that at least 95% of calibrated sensor analyte values are within 25% of actual analyte values as determined by analysis of blood obtained during a useful life of the sensor.

68. The method of claim 67, wherein the pre-implant calibration information comprises a value obtained from an in vitro calibration.

69. The method of claim 68, wherein the in vitro calibration is obtained by measuring at least two different analyte concentrations.

70. The method of claim 68, wherein the in vitro calibration is obtained at about 37 degrees C.

71. The method of claim 67, further comprising periodically recalibrating the sensor data after the initial calibration time period, wherein the periodically recalibrating is based on a reference analyte value.

72. The method of claim 71, wherein the reference analyte value is correlated with a time-shifted sensor data value.

73. The method of claim 71, wherein the periodically recalibrating comprises adjusting a sensor gain.

74. The method of claim 67, wherein the useful life is greater than about 3 days.

75. The method of claim 67, wherein the useful life is greater than about 5 days.

76. The method of claim 67, wherein the useful life is greater than about 7 days.

77. The method of claim 67, wherein the useful life is about one month.

78. The method of claim 67, wherein the analyte is glucose, and wherein the sensor is configured to respond substantially linearly to changes in glucose concentration at glucose concentrations ranging from about 40 mg/dL to about 500 mg/dL.

79. The method of claim 67, further comprising maintaining a stable sensor offset during a period of time of continuous measurement of an analyte concentration in the host.

80. The method of claim 67, further comprising determining trends in analyte concentration.

81. The method of claim 67, wherein the analyte is glucose.

82. The method of claim 67, further comprising recalibrating sensor data during the useful life of the sensor.

83. The method of claim 82, wherein the recalibrating is performed periodically throughout the useful life of the sensor.

84. The method of claim 82, wherein the recalibrating is based on reference data.

85. The method of claim 67, wherein calibration of the sensor data comprises using the pre-implant calibration information throughout the useful life of the sensor.

86. The method of claim 67, further comprising checking the calibration during the useful life of the sensor.

87. A system for processing sensor data from a continuous analyte sensor, comprising:

a sensor comprising an electrode configured for implantation in a subcutaneous tissue of a host, wherein the sensor is configured to continuously measure an analyte concentration, whereby sensor data associated with the subcutaneous analyte concentration is generated; and

electronic circuitry operably connected to the sensor and configured to perform an initial in vivo calibration of the sensor data using pre-implant calibration information, wherein the electronic circuitry is further configured to perform recalibration after an initial calibration time period; and

wherein the system is configured to provide a substantially accurate measurement of the analyte concentration in the host such that at least 95% of calibrated sensor analyte values as determined by analysis of blood obtained during a useful life of the sensor are within 25% of actual analyte values.

88. The system of claim 87, wherein the pre-implant calibration information comprises a value obtained from an in vitro calibration.

89. The system of claim 88, wherein the in vitro calibration is obtained by measuring at least two different analyte concentrations.

90. The system of claim 88, wherein the in vitro calibration is obtained at about 37 degrees C.

91. The system of claim 87, wherein the recalibration is based on a reference analyte value.

92. The system of claim 91, wherein the reference analyte value is correlated with a time-shifted sensor data value.

93. The system of claim 87, wherein the recalibration comprises an adjustment in sensor gain.

94. The system of claim 87, wherein the useful life is greater than about 3 days.

95. The system of claim 87, wherein the useful life is greater than about 5 days.

96. The system of claim 87, wherein the useful life is greater than about 7 days.

97. The system of claim 87, wherein the useful life is about one month.

98. The system of claim 87, wherein the analyte is glucose, and wherein the sensor is configured to respond substantially linearly to changes in glucose concentration at glucose concentrations ranging from about 40 mg/dL to about 500 mg/dL.

99. The system of claim 87, wherein the system is configured to provide a stable sensor offset during a period of time of continuous measurement of an analyte concentration in the host.

100. The system of claim 87, wherein the electronic circuitry is configured to determine trends in analyte concentration.

101. The system of claim 87, wherein the electronic circuitry is configured to physically couple the sensor.

102. The system of claim 87, wherein the electronic circuitry is configured to couple, via radio telemetry, to the sensor.

103. The system of claim 87, wherein the analyte is glucose.

104. The system of claim 87, wherein the electronic circuitry is configured to perform recalibration during the useful life of the sensor.

105. The system of claim 104, wherein the electronic circuitry is configured to perform the recalibration periodically throughout the useful life of the sensor.

106. The system of claim 104, wherein the recalibration is based on reference data.

107. The system of claim 87, wherein the electronic circuitry is configured to use the pre-implant calibration information for calibration of the sensor data throughout the useful life of the sensor.

108. The system of claim 87, wherein the electronic circuitry is configured to perform a calibration check during the useful life of the sensor.

109. The system of claim 87, wherein the sensor is configured to maintain a stability of calibration within 10% for one week.

110. A method for processing sensor data from a continuous analyte sensor, comprising:

receiving sensor data from an analyte sensor, the sensor data indicative of an analyte concentration in a host;

calibrating the sensor data, after insertion of the analyte sensor in the host, by using pre-implant calibration information;

recalibrating the sensor data after an initial calibration time period; and

generating, using an electronic system, a substantially accurate measurement of the analyte concentration, such that at least 95% of calibrated sensor analyte values are within 25% of actual analyte values as determined by analysis of blood obtained during a useful life of the sensor.

111. The method of claim 110, wherein the pre-implant calibration information comprises a value obtained from an in vitro calibration.

112. The method of claim 111, wherein the in vitro calibration is obtained by measuring at least two different analyte concentrations.

113. The method of claim 112, wherein the recalibrating is based on a reference analyte value.

114. The method of claim 113, wherein the reference analyte value is correlated with a time-shifted sensor data value.

115. The method of claim 111, wherein the in vitro calibration is obtained at about 37 degrees C.

116. The method of claim 110, wherein the recalibrating comprises adjusting a sensor gain.

117. The method of claim 110, wherein the useful life is greater than about 3 days.

118. The method of claim 110, wherein the useful life is greater than about 5 days.

119. The method of claim 110, wherein the useful life is greater than about 7 days.

120. The method of claim 110, wherein the useful life is about one month.

121. The method of claim 110, wherein the analyte is glucose, and wherein the sensor is configured to respond substantially linearly to changes in glucose concentration at glucose concentrations ranging from about 40 mg/dL to about 500 mg/dL.

122. The method of claim 110, further comprising maintaining a stable sensor offset during a period of time of continuous measurement of an analyte concentration in the host.

123. The method of claim 110, further comprising determining trends in analyte concentration.

124. The method of claim 110, wherein the analyte is glucose.

125. The method of claim 110, wherein recalibrating the sensor data is performed during the useful life of the sensor.

126. The method of claim 125, wherein recalibrating is based on reference data.

127. The method of claim 125, wherein recalibrating the sensor data is performed throughout the useful life of the sensor.

128. The method of claim 125, wherein recalibrating is performed periodically.

129. The method of claim 110, wherein calibration of the sensor data comprises using the pre-implant calibration information throughout the useful life of the sensor.

130. The method of claim 110, further comprising checking the calibration during the useful life of the sensor.