Calibration of fluidic devices

Abstract

The present invention provides methods of calibrating a fluidic device useful for detecting an analyte of interest in a bodily fluid. The invention also provides methods for assessing the reliability of an assay for an analyte in a bodily fluid with the use of a fluidic device. Another aspect of the invention is a method for performing a trend analysis on the concentration of an analyte in a subject using a fluidic device.

1 . A method of improving the accuracy of calibrating a fluidic system, comprising:
 a) providing a system for detecting an analyte in a bodily fluid from a subject comprising a fluidic device for providing said bodily fluid, said fluidic device having a calibration assembly and a reader assembly for detecting the presence of said analyte;   b) measuring one or more parameters of a calibration curve associated with said fluidic device;   c) comparing said one or more parameters with predetermined parameters associate with said fluidic device;   d) adjusting a signal output by the ratio of said one or more parameters and said predetermined parameters.   
     
     
         2 . The method of  claim 1  wherein said predetermined parameters are parameters determined at the time the fluidic device is manufactured. 
     
     
         3 . The method of  claim 2  wherein said predetermined parameters are replaced with said measured one or more parameters to be used in a calibration curve to scale a signal to determine said analyte concentration. 
     
     
         4 . A method of improving the calibration of a fluidic system, comprising:
 a) measuring a first signal in an original sample comprising a known quantity of an analyte:   b) measuring a second signal after spiking said original sample with a known quantity of said analyte;   c) plotting the difference between said first and second signals against a target value, wherein said target value is a signal expected for said known quantity of said analyte; and   d) arriving at a best fit of parameters by minimizing the sum of the square of the differences between said target value and calculated analyte values.   
     
     
         5 . The method of  claim 4  wherein said sample is provided to a fluidic device, said fluidic device comprising a sample collection unit and an assay assembly, wherein said sample collection unit allows a sample of bodily fluids to react with reactants contained within said assay assembly. 
     
     
         6 . A method of assessing the reliability of an assay for an analyte in a bodily fluid with the use of a fluidic device, comprising:
 a) providing a system, said system comprising a fluidic device, said fluidic device comprising a sample collection unit and an assay assembly, wherein said sample collection unit allows a sample of bodily fluid to react with reactants contained within said assay assembly, for detecting the presence of an analyte in a bodily fluid from a subject, and a reader assembly for detecting the presence of said analyte;   b) sensing with a sensor a change in operation parameters under which the system normally operates.   
     
     
         7 . The method of  claim 6  further comprising improving the reliability of said assay by adjusting the operating parameters to effect normal functioning of the system. 
     
     
         8 . The method of  claim 6  wherein said sensor is associated with said fluidic device. 
     
     
         9 . The method of  claim 8  where said sensor is capable of communicating said change to said reader assembly. 
     
     
         10 . The method of  claim 6  wherein said change comprises a change in temperature. 
     
     
         11 . The method of  claim 6  wherein said change comprises a change in pressure. 
     
     
         12 . The method of  claim 6  where said sensor is associated with said reader assembly. 
     
     
         13 . The method of  claim 12  where said sensor is capable of communicating said change to an external device. 
     
     
         14 . The method of  claim 12  wherein said change comprises a change in temperature. 
     
     
         15 . The method of  claim 12  wherein said change comprises a change in pressure. 
     
     
         16 . The method of  claim 6 , further comprising adjusting a calibration step of said system. 
     
     
         17 . The method of  claim 6 , further comprising wirelessly communicating said change via a handheld device. 
     
     
         18 . The method of  claim 6  wherein said change is the presence of moisture in said fluidic device. 
     
     
         19 . The method of  claim 18  wherein said sensor comprises thiocyanate and iron salt. 
     
     
         20 . A method of performing a trend analysis on the concentration of an analyte in a subject, comprising:
 a) providing a fluidic device comprising at least one sample collection unit, an immunoassay assembly containing immunoassay reagents, a plurality of channels in fluid communication with said sample collection unit and/or said immunoassay assembly;   b) actuating said fluidic device and directing said immunoassay reagents within said fluidic device;   c) allowing a sample of bodily fluid of less than about 500 ul to react with said immunoassay reagents contained within said assay immunoassay assembly to yield a detectable signal indicative of the presence of said analyte in said sample;   d) detecting said detectable signal generated from said analyte collected in said sample of bodily fluid; and   e) repeating steps a) through d) for a single patient over a period of time to detect concentrations of said anayte, thereby performing said trend analysis.