# US 2021/0239587 A1 · Monitoring an immunoassay > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0239587 A1 - Document ID: US20210239587A1 - Status: Published application - Kind: A1 - Application number: 17/175,801 - Filed: 2021-02-15 - Published: 2021-08-05 - Earliest claimed: 2007-06-20 - Assignees: Abbott Toxicology Limited - Applicants: Abbott Toxicology Limited - Inventors: Timothy John Abbott; David Patrick Edward Brookes - Web page: https://patentgrep.com/patent/US20210239587A1 ## CPC - G01N 11/02: by measuring flow of the material - G01N 33/54306: {Solid-phase reaction mechanisms} - G01N 33/54388: {based on lateral flow} - G01N 33/558: using diffusion or migration of antigen or antibody {(immunochromatographic test strips G01N33/54387)} - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) ## Abstract A method of monitoring an immunoassay comprises determining the shape of the flow edge of fluid across an immunoassay region. This allows, for example, early detection of possible errors in the test. The above methods may also be used to provide methods to improve the run conditions of a test during its development. The method may be applied to a competitive assay. ## Claims ### Claim at position 1 1-10. (canceled) ### Claim 11 A method for monitoring the quality of an immunoassay, said method comprising: introducing a test sample onto an immunoassay strip; detecting the start of fluid flow on the immunoassay strip; monitoring the flow of fluid along the immunoassay strip by monitoring a position of a flow edge as a function of time for the duration of fluid flow on an active area of the immunoassay strip; calculating the speed of movement of the position of the flow edge; calculating the time interval expected for the flow edge to reach the end of the active area of the immunoassay strip using the position of the flow edge, a speed of the movement of the flow edge, and/or the elapsed time since detecting the start of fluid flow; using the time interval expected for the flow edge to reach the end of the active area of the immunoassay strip to identify an optimal time to read a result on the immunoassay test strip. ### Claim 12 (depends on 11) The method of claim 11 further comprising: measuring the time interval from introducing the test sample onto the immunoassay strip and detecting the start of fluid flow on the immunoassay strip; and alerting a user of a problem with the immunoassay if the time interval is greater than a pre-determined threshold value and/or instructing the user to add more sample to the immunoassay strip and/or adding a run solution to the immunoassay strip. ### Claim 13 (depends on 11) The method of claim 11, further comprising starting a timer upon detecting the start of fluid flow on the immunoassay strip. ### Claim 14 (depends on 11) The method of claim 11, wherein monitoring the position of the flow edge comprises obtaining a first image of the active area at a first time and obtaining a second image of the active area at a second time that is after the first time; and subtracting the first image from the second image to produce a subtraction image. ### Claim 15 (depends on 14) The method of claim 14, further comprising applying a high-pass filter to the subtraction image and/or applying a thresholding process to the subtraction image. ### Claim 16 (depends on 11) The method of claim 11, wherein monitoring the position of the flow edge comprises detecting the position of the flow edge in a single image. ### Claim 17 (depends on 11) The method of claim 11, further comprising: determining a shape of the flow edge; and alerting a user of a problem with the immunoassay if the shape of the flow edge is uneven. ### Claim 18 (depends on 11) The method of claim 11, further comprising calculating a change in the speed of movement of the position of the flow edge. ### Claim 19 (depends on 11) The method of claim 11, wherein monitoring the flow of fluid along the immunoassay strip comprises recording a series of images of the active area, wherein successive images of said series are recorded at time intervals of less than a second to approximately every 1-5 seconds. ### Claim 20 (depends on 11) The method of claim 11, further comprising alerting a user of a problem with the immunoassay if the speed is greater than a pre-determined threshold value. ### Claim 21 (depends on 11) The method of claim 11, further comprising alerting a user of a problem with the immunoassay if the speed is less than a pre-determined threshold value. ### Claim 22 (depends on 21) The method of claim 21, further comprising prompting a user to add more sample and/or applying a run solution to the immunoassay strip. ### Claim 23 (depends on 11) The method of claim 11, further comprising recording the value of an environmental factor. ### Claim 24 (depends on 23) The method of claim 23, wherein said environmental factor is humidity, ambient temperature, or tilt of the immunoassay. ### Claim 25 (depends on 11) The method of claim 11, wherein said environmental factor is used to determine an upper and/or lower threshold for the speed of movement of the position of the flow edge and/or to apply a correction to the measured speed of movement of the position of the flow edge. ### Claim 26 (depends on 11) The method of claim 11, wherein the speed of movement of the position of the flow edge is used as an indicator of the quality of the immunoassay and/or to determine a cut-off for determining a positive or negative result of the immunoassay. ### Claim 27 (depends on 11) The method of claim 11, further comprising detecting that the position of the flow edge is at the end of the active zone. ### Claim 28 (depends on 27) The method of claim 27, further comprising determining an optimal incubation time for the immunoassay and calculating a remaining incubation time. ### Claim 29 (depends on 11) The method of claim 11, comprising using two immunoassay strips and comparing a first speed of movement of a first position of a first flow edge on a first test strip with a second speed of movement of a second position of a second flow edge on a second test strip to provide a difference in speed for the two immunoassay strips. ### Claim 30 (depends on 29) The method of claim 29, wherein the difference in speed for the two immunoassay strips provides a test result.