Microbiology Methods for ERP Review 3-2020

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j. Load the Negative and Positive Controls in each position specified by the instrument. k. Prepare and dispense the correct amount of Activated Washing Buffer. l. Verify all disposable containers do not need emptying. m. When the run is completed, open the lid to the Dynex DS2 instrument and remove the loading trays with the sample test tubes by pulling the loading trays out away from the instrument. Discard sample test tubes in the proper location according to laboratory procedures. n. Discard the reagent tubes, negative controls, and positive controls in the proper location according to laboratory procedures. Note: Reagents may be capped and refrigerated at 2–8°C with the rest of the remaining kit. o. To view a report on a completed run, select the desired result file in the “Recent Test” Box, and select the “Report” button. p. The report can be viewed and printed from the report display screen. q. The results are displayed in a 96 well format with each individual optical density reading. r. A secondary file which can be used to export the results into a LIMS system is created in a folder on the desktop called “ELISA Export Results”, this is in a CSV (comma separated values) file format. s. Interpretation: The presence or absence of the pathogen is expressed as optical density (OD 450 ) measurements using the Dynex DS2 instrument plate reader or a microplate reader with a 450 nm filter where a Dynex DS2 instrument is unavailable. For control assay acceptance criteria, a result of an OD 450 < 0.100 is valid for a Negative Control, whereas a result of an OD 450 > 0.500 is valid for a Positive Control. A result of an OD 450 < 0.200 is negative for Salmonella . A result of an OD 450 ≥ 0.200 is considered presumptive positive for Salmonella . 5) Manual Procedure : Remove the kit from storage at 2–8°C an hour before use to allow the components to reach room temperature (15–25°C). Determine the number of wells required for the test. Take the required number of strips from the pouch and fit them to the framer provided. Note: Unused strips should be returned to the pouch and stored at 2–8°C. a. Prepare the Washing Buffer by adding the contents of a single Washing Buffer Activator sachet and Washing Buffer bottle (60 mL) to 1440 mL or a single Washing Buffer Activator sachet and Washing Buffer bottle (10 mL) to 240 mL of deionized water to prepare the washing buffer at assay concentration. Mix until the activator has fully dissolved.

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