Analyte Monitoring Device And Methods Of Use

Abstract

An analyte monitor includes a sensor, a sensor control unit, and a display unit. The sensor has, for example, a substrate, a recessed channel formed in the substrate, and conductive material disposed in the recessed channel to form a working electrode. The sensor control unit typically has a housing adapted for placement on skin and is adapted to receive a portion of an electrochemical sensor. The sensor control unit also includes two or more conductive contacts disposed on the housing and configured for coupling to two or more contact pads on the sensor. A transmitter is disposed in the housing and coupled to the plurality of conductive contacts for transmitting data obtained using the sensor. The display unit has a receiver for receiving data transmitted by the transmitter of the sensor control unit and a display coupled to the receiver for displaying an indication of a level of an analyte. The analyte monitor may also be part of a drug delivery system to alter the level of the analyte based on the data obtained using the sensor.

1 . A sensor control unit comprising:
 a housing adapted for placement on skin and adapted to receive a portion of an electrochemical sensor having a plurality of contact pads;   a plurality of conductive contacts disposed on the housing and configured for coupling to the plurality of contact pads on the sensor; and   a transmitter disposed in the housing and coupled to the plurality of conductive contacts for transmitting data obtained using the sensor.   
     
     
         2 - 120 . (canceled) 
     
     
         121 . A method for matching continuous glucose sensor data with reference data, the method comprising:
 receiving sensor data from a continuous glucose sensor, the sensor data comprising one or more sensor data points;   receiving reference data from a reference glucose monitor, the reference data comprising one or more reference data points;   forming a matched pair by pairing a sensor value with a reference value, wherein the sensor value comprises a sensor data point or an averaged sensor data point, and wherein the reference value comprises a reference data point or an averaged reference data point; and   calibrating the sensor data in real time, wherein the sensor data is calibrated using at least the matched pair.   
     
     
         122 . The method of  claim 121 , wherein the step of forming the matched pair comprises averaging a plurality of reference data points to obtain the reference value. 
     
     
         123 . The method of  claim 122 , wherein the step of averaging comprises at least one of weighted averaging and calculating a mean. 
     
     
         124 . The method of  claim 121 , wherein the step of forming the matched pair comprises averaging a plurality of time corresponding sensor data points to obtain the sensor value. 
     
     
         125 . The method of  claim 124 , wherein the step of averaging comprises at least one of weighted averaging and calculating a mean. 
     
     
         126 . The method of  claim 121 , wherein the step of forming the matched pair comprises averaging a plurality of reference data points to obtain the reference value and averaging a plurality of sensor data points to obtain the sensor value. 
     
     
         127 . The method of  claim 121 , wherein the one or more sensor data points are obtained at a time that is at least about 10 minutes after a time at which the one or more reference data points are obtained. 
     
     
         128 . The method of  claim 121 , wherein the one or more sensor data points are obtained at a time after the one or more reference data points are obtained. 
     
     
         129 . The method of  claim 121 , wherein the step of forming the matched pair comprises evaluating a plurality of matched pairs, wherein the plurality of matched pairs are obtained by matching a reference data point against a plurality of time spaced sensor data points. 
     
     
         130 . The method of  claim 129 , wherein the step of forming the matched pair comprises choosing from the plurality of matched pairs a matched pair with a best correlation. 
     
     
         131 . A system for matching continuous glucose sensor data with reference data, the system comprising:
 a sensor data module configured to receive a data stream from a continuous glucose sensor, the sensor data comprising one or more sensor data points;   a reference data module configured to receive reference data from a reference glucose monitor, the reference data comprising one or more reference data points; and   a processor module configured to form a matched pair by pairing a sensor data point with a reference data point, wherein the processor module is further configured to calibrate sensor data in real time, wherein the sensor data is calibrated using at least said matched data pair.   
     
     
         132 . The system of  claim 131 , wherein the processor module is configured to average a plurality of reference data points to obtain a reference value. 
     
     
         133 . The system of  claim 132 , wherein the processor module is configured to average the plurality of reference data points using at least one of a weighted average and a mean value. 
     
     
         134 . The system of  claim 131 , wherein the processor module is configured to average a plurality of time corresponding sensor data points to obtain a sensor value. 
     
     
         135 . The system of  claim 134 , wherein the processor module is configured to average the plurality of sensor data points using at least one of a weighted average and a mean value. 
     
     
         136 . The system of  claim 131 , wherein the processor module configured to average a plurality of reference data points to obtain a reference value and to average a plurality of sensor data points to obtain a sensor value. 
     
     
         137 . The system of  claim 136 , wherein the sensor value is measured at a time that is at least about 10 minutes after a time at which the reference value is measured. 
     
     
         138 . The system of  claim 136 , wherein the sensor value is measured at a time after the reference value is measured. 
     
     
         139 . The system of  claim 131 , wherein the processor module is further configured to evaluate a plurality of matched pairs, wherein the plurality of matched pairs are obtained by matching a reference data point against a plurality of time spaced sensor data points. 
     
     
         140 . The system of  claim 139 , wherein the processor module is further configured to choose from the plurality of matched pairs, a matched pair with the best correlation. 
     
     
         141 . A method for calibrating a continuous glucose sensor data, the method comprising:
 receiving a data stream from a continuous glucose sensor, the data stream comprising one or more sensor data points;   receiving reference data from a reference glucose monitor, the reference data comprising one or more reference data points;   forming at least one matched pair by pairing one or more sensor data points with one or more reference data points;   forming a first calibration line and a second calibration line that have different slopes; and   calibrating the one or more sensor data points in real time, wherein the first calibration line is applied when a blood glucose concentration is at or below a predetermined threshold, and wherein the second calibration line is applied when a blood glucose concentration is at or above the predetermined threshold   
     
     
         142 . The method of  claim 141 , wherein the predetermined threshold is 150 mg/dL. 
     
     
         143 . A system for calibrating continuous glucose sensor data, the system comprising:
 a sensor data module configured to receive a data stream from a continuous glucose sensor, the data stream comprising one or more sensor data points;   a reference input module configured to receive reference data from a reference glucose monitor, the reference data comprising one or more reference data points;   a processor module configured to form at least one matched pair by pairing one or more sensor data points with one or more reference data points;   wherein the processor module is further configured to form a first calibration line and a second calibration line that have different slopes, and wherein at least one of the two calibration lines is based at least in part on the at least one matched pair; and   calibrating the one or more sensor data points in real time, wherein the first calibration line is applied when a blood glucose concentration is at or below a predetermined threshold, and wherein the second calibration line is applied when a blood glucose concentration is at or above the predetermined threshold   
     
     
         144 . The system of  claim 143 , wherein the predetermined threshold is 150 mg/dl. 
     
     
         145 . An integrated system, comprising:
 a continuous glucose sensor configured to measure a glucose concentration in a host and to provide sensor data associated therewith; and   an insulin delivery device configured to administer insulin, wherein the insulin delivery device comprises a processor module configured to receive and store, at least temporarily, sensor data obtained from the continuous glucose sensor, and wherein the processor module is further configured to analyze sensor data to predict a future glucose concentration in the host, whereby insulin is administered at least in part responsive to the predicted future glucose concentration.   
     
     
         146 . The integrated system of  claim 145 , wherein the processor module is configured to administer insulin, via the delivery device, responsive to a predicted future glucose concentration below a predetermined threshold. 
     
     
         147 . The system of  claim 145 , wherein the processor module is configured to determine an amount and time of insulin administration based, at least in part, on the predicted future glucose concentration. 
     
     
         148 . The system of  claim 145  wherein the insulin delivery device comprises an insulin pump. 
     
     
         149 . An integrated system, comprising:
 a continuous glucose sensor configured to measure a glucose concentration in a host and to provide sensor data associated therewith; and   an insulin delivery device configured to administer insulin, wherein the insulin delivery device comprises a processor module configured to receive and store, at least temporarily, sensor data obtained from the continuous glucose sensor, wherein the processor module is further configured to analyze sensor data to determine a rate of change of glucose concentration in the host, whereby insulin is administered at least in part responsive to the rate of change.   
     
     
         150 . The integrated system of  claim 145 , wherein the processor module is configured to administer insulin, via the delivery device, responsive to a rate of change glucose concentration above a predetermined threshold. 
     
     
         151 . The system of  claim 145 , wherein the processor module is configured to determine an amount and time of insulin administration based, at least in part, on the rate of change. 
     
     
         152 . The system of  claim 149  wherein the insulin delivery device comprises an insulin pump. 
     
     
         153 . An integrated system, comprising:
 a continuous glucose sensor configured to measure a glucose concentration in a host and provide sensor data associated therewith; and   an insulin delivery device configured to administer insulin, wherein the insulin delivery device comprises a processor module configured to receive and store, at least temporarily, sensor data obtained from the continuous glucose sensor, wherein the processor module is further configured to analyze sensor data to determine a glucose trend in the host, whereby insulin is administered at least in part responsive to the glucose trend.   
     
     
         154 . The system of  claim 145 , wherein the processor module is configured to determine an amount and time of insulin administration based, at least in part, on the glucose trend. 
     
     
         155 . The system of  claim 153  wherein the insulin delivery device comprises an insulin pump. 
     
     
         156 . A method for determining at least one of an amount of insulin to be administered or a duration of time of insulin administration, the method comprising:
 receiving continuous glucose sensor data, the sensor data comprising one or more sensor data points;   processing said glucose sensor data to determine at least one of an amount of insulin to be administered or a duration of time of insulin administration by analyzing a glucose trend in the sensor data; and   instructing an insulin delivery device to deliver insulin, the instruction comprising at least one of the amount of insulin to be administered or the duration of time of insulin administration, responsive to the glucose trend.   
     
     
         157 . The method of  claim 156 , wherein the step of analyzing the glucose trend comprises predicting a future glucose concentration. 
     
     
         158 . The method of  claim 156 , wherein the step of analyzing the glucose trend comprises determining a rate of change. 
     
     
         159 . A glucose sensor system, comprising:
 a glucose sensor; and   sensor electronics configured to receive and retain glucose data from the glucose sensor;
 wherein the sensor electronics are configured to process the glucose data to predict a glucose related trend. 
   
     
     
         160 . The system of  claim 159 , wherein the glucose related trend comprises a rate of glucose increase or a rate of glucose decrease. 
     
     
         161 . The system of  claim 159 , wherein the glucose related trend comprises an acceleration of glucose increase or an acceleration of glucose decrease. 
     
     
         162 . The system of  claim 159 , wherein the sensor electronics comprises a readable/writable memory device that retains the glucose data 
     
     
         163 . The system of  claim 159 , further comprising a receiver configured to display the glucose related trend. 
     
     
         164 . A glucose monitoring device, comprising:
 a sensor data module configured to receive glucose data from a continuous glucose sensor;   a data storage module coupled to the sensor data module and configured to store glucose data; and   a processor configured to process the stored glucose data to predict a glucose related trend.   
     
     
         165 . The device of  claim 164 , wherein the glucose related trend comprises a rate of glucose level increase or a rate of glucose level decrease. 
     
     
         166 . The device of  claim 164 , wherein the glucose related trend comprises an acceleration of glucose level increase or an acceleration of glucose level decrease. 
     
     
         167 . The device of  claim 164 , wherein the data storage unit comprises a readable/writable memory device. 
     
     
         168 . The device of  claim 164 , further comprising a user interface configured to display the glucose related trend. 
     
     
         169 . The device of  claim 164 , further comprising a communication unit operatively coupled to the processor, the communication unit configured to transmit one or more of the glucose data or the glucose related trend. 
     
     
         170 . The device of  claim 169 , wherein the communication unit comprises a wireless communication unit. 
     
     
         171 . The device of  claim 169 , wherein the communication unit comprises an RF transmitter. 
     
     
         172 . The device of  claim 171 , wherein the communication unit comprises an RF transceiver. 
     
     
         173 . A method of processing glucose data, comprising:
 positioning at least a portion of a glucose sensor in contact with a bodily fluid of a host;   obtaining glucose related information using the sensor;   storing the glucose related information; and   processing the stored glucose related information and predicting glucose related trend.   
     
     
         174 . The method of  claim 173 , further comprising displaying the glucose related trend. 
     
     
         175 . A method for calibrating a continuous glucose sensor, comprising:
 positioning at least a portion of an electrochemical sensor in a body of a host;   obtaining one or more sensor data points from the electrochemical sensor;   determining a rate of change from the one or more sensor data points; and   determining whether calibration is appropriate based on the determined rate of change.   
     
     
         176 . The method of  claim 175 , wherein determining whether calibration is appropriate comprises comparing the determined the rate of change to a predetermined rate of change threshold. 
     
     
         177 . The method of  claim 176 , wherein when the determined rate of change is above the predetermined rate of change threshold, calibration is determined to be not appropriate. 
     
     
         178 . The method of  claim 175 , further comprising waiting a predetermined time period before performing calibration. 
     
     
         179 . The method of  claim 178  wherein when the determined rate of change is below the predetermined value, calibration is determined to be appropriate. 
     
     
         180 . The method of  claim 175  further comprising performing calibration using a blood sample to calibrate the electrochemical sensor signal. 
     
     
         181 . A method of glucose determination, comprising:
 positioning at least a portion of an electrochemical sensor in a body of a host;   obtaining one or more sensor data points from the electrochemical sensor; and   performing a rate of change analysis based on the one or more sensor data points.   
     
     
         182 . The method of  claim 181 , wherein the rate of change analysis comprises determining whether calibration is appropriate. 
     
     
         183 . A glucose sensor system, comprising:
 an electrochemical glucose sensor; and   a receiver configured to receive one or more sensor data points from an electrochemical sensor, the receiver further configured to determine a rate of change of the one or more sensor data points and to determine whether calibration is appropriate based on the determined rate of change.   
     
     
         184 . The device of  claim 183 , further comprising a user interface operatively coupled to the receiver configured to display one or more data associated with at least one of the one or more sensor data points, the rate of change, and the determination whether calibration is appropriate. 
     
     
         185 . A method for processing sensor data from a continuous glucose sensor, the method comprising:
 receiving sensor data from a continuous glucose sensor;   processing the received sensor data to form first processed sensor data; and   processing the first processed sensor data to obtained second processed sensor data.   
     
     
         186 . The method of  claim 185 , wherein the step of processing the received sensor data and the step of processing the first processed sensor data are performed in separate electronics units. 
     
     
         187 . The method of  claim 185 , wherein the step of processing the received sensor data and the step of processing the first processed sensor data are performed in a single or integral electronics unit 
     
     
         188 . The method of  claim 185 , wherein the step of processing the received sensor data is performed in a sensor electronics, wherein the sensor electronics are integral with the continuous glucose sensor, and wherein the step of processing the first processing sensor data is performed in a receiver electronics, wherein the receiver electronics are separate from the sensor electronics, and wherein the sensor electronics are operatively connected to the receiver electronics by a wired or wireless connection. 
     
     
         189 . A system for processing sensor data from a continuous glucose sensor, the system comprising:
 a sensor data module configured to receive sensor data from a continuous glucose sensor; and   a processor module configured to process the received sensor data to form first processed sensor data, wherein the processor module is further configured to process the first processed sensor data to obtain second processed sensor data.   
     
     
         190 . The system of  claim 189 , wherein processing the received sensor data to form first processed sensor data and processing the first processed sensor data to obtain second processed sensor data are performed in separate electronics units. 
     
     
         191 . The system of  claim 189 , wherein processing the received sensor data to form first processed sensor data and processing the first processed sensor data to obtain second processed sensor data are performed in a single or integral electronics unit 
     
     
         192 . The system of  claim 189 , wherein the system further comprises sensor electronics directly connected to the continuous glucose sensor, wherein the first processed sensor data is obtained from the sensor electronics, and wherein the system further comprises receiver electronics operative connected to the sensor electronics, wherein the second processed sensor data is obtained from the receiver electronics, wherein the receiver electronics are separate from the sensor electronics, and wherein the sensor electronics are operatively connected to the receiver electronics by a wired or wireless connection. 
     
     
         193 . A method for predicting future data from real time continuous glucose sensor data, the method comprising:
 receiving sensor data from a continuous glucose sensor, the sensor data comprising one or more sensor data points; and   predicting one or more glucose values for a future time, based at least in part on the sensor data.   
     
     
         194 . The method of  claim 193 , further comprising:
 receiving reference data from a reference glucose monitor, the reference data comprising one or more reference data points;   forming at least one matched pair by pairing one or more sensor data points with one or more reference data points; and   forming a conversion function based, at least in part, on said at least one matched pair, wherein the step of predicting one or more glucose values comprises calculating the one or more future glucose values based, at least in part, on the conversion function   
     
     
         195 . The method of  claim 193 , further comprising a step of alerting a user when one or more predicted glucose values indicates an upcoming hypoglycemic event or an upcoming hyperglycemic event. 
     
     
         196 . The method of  claim 193 , further comprising a step of estimating one or more glucose values for a future time, such that an estimate of a glucose value at an instant time can be displayed. 
     
     
         197 . The method of  claim 196 , further comprising displaying a glucose value estimate on a user interface. 
     
     
         198 . The method of  claim 193 , further comprising a step of processing sensor data by estimating one or more glucose values for a future time, such that an estimate of a glucose value at an instant time can be displayed. 
     
     
         199 . The method of  claim 198 , further comprising displaying the time compensated glucose value estimate on a user interface. 
     
     
         200 . A system for predicting future data from real time continuous glucose sensor data, the system comprising:
 a sensor data module configured to receive sensor data from a continuous glucose sensor, the sensor data comprising one or more sensor data points; and   a processor module configured to predict one or more glucose values for a future time, based at least in part on the sensor data.   
     
     
         201 . The system of  claim 200 , further comprising:
 a reference input module configured to receive reference data from a reference glucose monitor, the reference data comprising one or more reference data points, and wherein the processor module is further configured to form at least one matched pair by pairing a one or more sensor data points with one or more reference data points and form a conversion function based, at least in part, on said at least one matched pair, wherein one or more glucose values is predicted by calculating one or more future glucose values based, at least in part, on the conversion function.   
     
     
         202 . The system of  claim 200 , further comprising an output module configured to alert a user when one or more predicted glucose values indicates an upcoming hypoglycemic event or an upcoming hyperglycemic event. 
     
     
         203 . The system of  claim 200 , wherein the processor module is configured to estimate one or more glucose values for a future time, such that an estimate of a glucose value at an instant time can be displayed. 
     
     
         204 . The system of  claim 203 , further comprising an output module configured to display the estimated glucose value estimate on a user interface. 
     
     
         205 . The system of  claim 200 , wherein the processor module is configured to process the sensor data by estimating one or more glucose values for a future time, such that an estimate of a glucose value at an instant time can be displayed. 
     
     
         206 . The system of  claim 200 , further comprising an output module configured to display the glucose value estimate on a user interface. 
     
     
         207 . A continuous glucose sensing system, the system comprising:
 a continuous glucose sensor device comprising a first sensor configured to continuously measuring a glucose concentration in a host, wherein at least a portion of the first sensor is positioned in or under a host's tissue;   a glucose monitor comprising a second sensor configured to determine a glucose concentration of the host at a point in time; and   a processor module configured to calibrate data from said first sensor using data from said second sensor, and wherein the second sensor is integral with at least a portion of the continuous glucose sensor device.   
     
     
         208 . The system of  claim 207 , wherein the continuous glucose sensor device comprises a receiver configured to receive and display continuous glucose data from the first sensor. 
     
     
         209 . The system of  claim 208 , wherein the glucose monitor further comprises a blood glucose meter, and wherein the meter is integral with the receiver. 
     
     
         210 . A method of calibrating, the method comprising:
 inserting at least a portion of a first sensor in a host's tissue; and   calibrating the first sensor unit after a predetermined time period has lapsed from the inserting step.   
     
     
         211 . The method of  claim 210 , wherein the calibrating step further comprises a step of performing a blood glucose measurement after the predetermined time period has lapsed from the inserting step. 
     
     
         212 . An analyte monitoring system, comprising:
 a sensor device including a sensor, the sensor device configured to receive a data stream corresponding to a glucose concentration in a host, the data stream comprising one or more sensor data points; and   a display unit operatively coupled to the sensor, the display unit configured to output data based on signals received from the sensor device.   
     
     
         213 . The system of  claim 212 , wherein the data output comprises at least one output selected from the group consisting of a series of audio alerts, a series of vibratory alerts, a series of visual alerts, and a series of a combination of one or more of audio, visual or vibratory alerts. 
     
     
         214 . An analyte monitoring device, comprising:
 a receiver unit for receiving one or more signals related to an analyte level in a host detected by an electrochemical sensor, the receiver unit comprising a display to display an indication of the analyte level wherein the receiver unit comprises a calibrator.   
     
     
         215 . The device of  claim 214 , wherein the receiver unit comprises an RF receiver. 
     
     
         216 . The device of  claim 214 , wherein the receiver unit comprises an analyzer coupled to the display and the RF receiver to analyze data from the RF receiver and provide analyzed data to the display. 
     
     
         217 . The device of  claim 214 , wherein the calibrator is a blood glucose calibrator. 
     
     
         218 . The device of  claim 214 , wherein the receiver unit comprises an alarm configured to indicate when the analyte level is at or near a threshold level. 
     
     
         219 . The device of  claim 218 , wherein the threshold level comprises at least one level selected from the group consisting of hypoglycemia, predicted future hypoglycemia, hyperglycemia, or predicted future hyperglycemia. 
     
     
         220 . The device of  claim 218 , wherein the alarm comprises at least one alarm selected from the group consisting of an audible signal, a visual display, or a vibratory signal. 
     
     
         221 . The device of  claim 214  wherein the receiver unit is a portable handheld unit. 
     
     
         222 . The device of  claim 214  wherein the receiver unit is configured for wearing on or under an article of clothing. 
     
     
         223 . The device of  claim 214 , wherein the receiver unit includes an RF transceiver configured to receive or transmit the one or more signals related to an analyte level. 
     
     
         224 . The device of  claim 214 , wherein the analyte is glucose. 
     
     
         225 . The device of  claim 214 , wherein the receiver unit is further configured to communicate with a drug administration system. 
     
     
         226 . The device of  claim 225 , wherein the receiver unit is configured to wirelessly communicate with the drug administration system. 
     
     
         227 . The device of  claim 226 , wherein the receiver unit is configured to communicate with the drug administration system by RF communication. 
     
     
         228 . The device of  claim 214 , wherein the receiver unit is configured to display one or more indicators associated with the analyte level on the display. 
     
     
         229 . The device of  claim 228 , wherein the one or more indicators comprises one or more of an arrow or a color representative of analyte level trend information. 
     
     
         230 . The device of  claim 228 , wherein the displayed one or more indicators comprises a historical analyte level or a predicted analyte level of the host. 
     
     
         231 . The device of  claim 228 , wherein the displayed one or more indicators corresponds to a rate of change in the analyte level detected by the electrochemical sensor. 
     
     
         232 . A system for calibrating a glucose sensor, the system comprising:
 a continuous glucose sensor configured to substantially continuously measure a glucose concentration in a host and to provide sensor data associated therewith;   a reference glucose monitor configured to measure the host's blood glucose concentration at a time point and provide reference data associated therewith; and   a processor module, configured to form at least one matched data pair by matching reference analyte data to substantially time corresponding sensor data, wherein the processor module is further configured determine a rate of change of the glucose concentration at time substantially corresponding to the at least one matched data pair and to determine whether to calibrate the continuous glucose sensor responsive thereto.   
     
     
         233 . The system of  claim 232 , further comprising a receiver unit operatively connected to the continuous glucose sensor and configured to receive and process the sensor data, wherein the processor module and reference glucose monitor are integral with the receiver unit. 
     
     
         234 . The system of  claim 232 , wherein the processor module is further configured to instruct administration of insulin at least in part responsive to the rate of change. 
     
     
         235 . The system of  claim 234 , wherein the processor module is further configured to predict a future glucose concentration. 
     
     
         236 . The system of  claim 232 , wherein the processor module is configured to wait a predetermined time period before performing calibration. 
     
     
         237 . A system for calibrating a glucose sensor, the system comprising:
 a continuous glucose sensor configured to substantially continuously measure a glucose concentration in a host and to provide sensor data associated therewith;   a reference glucose monitor configured to measure a host's blood glucose concentration at a time point and provide reference data associated therewith; and   a processor module configured to form at least one matched data pair by matching reference analyte data to substantially time corresponding sensor data, wherein the processor module is further configured evaluate a congruence of at least one matched data pair and to determine whether to calibrate the sensor responsive thereto.   
     
     
         238 . The system of  claim 237 , further comprising a receiver unit operatively connected to the continuous glucose sensor and configured to receive and process the sensor data, wherein the processor module and reference glucose monitor are integral with the receiver unit. 
     
     
         239 . The system of  claim 234 , wherein the processor module is further configured to predict a future glucose concentration. 
     
     
         240 . The system of  claim 239 , wherein the processor module is further configured to instruct administration of insulin at least in part responsive to the predicted future glucose concentration. 
     
     
         241 . The system of  claim 232 , wherein the processor module is configured to wait a predetermined time period before performing calibration. 
     
     
         242 . A system for calibrating a glucose sensor, the system comprising:
 a continuous glucose sensor configured to substantially continuously measure a glucose concentration in a host and to provide sensor data associated therewith;   a reference glucose monitor configured to measure the host's blood glucose concentration at a time point and to provide reference data associated therewith;   and a processor module, configured to form at least one matched data pair by matching reference analyte data to substantially time corresponding sensor data, wherein the processor module is further configured evaluate physiological changes of the host at time substantially corresponding to the at least one matched data pair and to determine whether to calibrate the continuous glucose sensor responsive thereto.   
     
     
         243 . The system of  claim 232 , further comprising a receiver unit operatively connected to the continuous glucose sensor and configured to receive and process the sensor data, wherein the processor module and reference glucose monitor are integral with the receiver unit. 
     
     
         244 . The system of  claim 232 , wherein the processor module is further configured to instruct administration of insulin at least in part responsive to the physiological changes.