5 Tips for Quality Control of your ELISA Assays

Posted on April 20, 2011 by Magdalene Laszczak

The enzyme-linked immunosorbent assay (ELISA) is one of the most sensitive and reproducible assays available. The reproducibility and reliability of the ELISA assays are dependent on proper laboratory technique and careful attention to detail which can cause large variation in the results. There are many different sources of variability of assay results.

Running Control Samples
To ensure quality control of ELISA assays, it’s important to run assaying control samples across the analytical range of the assay, such as low, medium and high controls. Such controls are typically made from your source analyte and be in the same matrix as your critical samples. By using your source analyte, it’s easy to spot any variation between ELISA assay runs and kit lots.
Replicate Analysis
Another approach to quality control for your ELISA analysis is replicate analysis which is the repetition of an experiment in order to test the validity of its results. This will allow you to quantify your precision and yield lower %CV. When performing the analysis of the data results it’s important to look at such criteria as %CV and lower limit of detection (LLOD) which will give you criteria for which data points to eliminate.
Testing for Precision
Precision is the ability of the assay to consistently reproduce a result when sub-samples are taken from the same specimen. Within-assay and inter-assay, precision are two distinct measures that can be made as part of the quality control procedure. There are software programs available that can help you quickly spot such variation in your data.
Test Storage Conditions
To ensure total quality control of the assay, it’s import to perform stability studies on the storage conditions for your controls. This will verify that your storage conditions are adequate enough and will not cause variation in your assays.
Laboratory Technique
There are also other non-assay sources of variation that need to be addressed when performing quality control for your ELISA assay. These include how the samples are taken, transported, aliquoted and proper laboratory technique. Once the ELISA assay has been validated, the continued satisfactory performance should be continually monitored by the set quality control process.

When the sources of the ELISA assay variation are identified, it’s simple to implement corrective procedures. The purpose of such quality assessment is to confirm that your ELISA results generated are consistent over time.

10 Tips for MasterPlex QT v4.0 Power Users

Posted on June 30, 2009 by Charles Ma

MasterPlex QT v4.0 has come a long way since the previous version and although there has been many updates since the initial release, some of these powerful features can easily sneak by unwary users. Let’s go through this list of what I think are the 10 most valuable and time-saving features for any MasterPlex QT v4.0 Power User:

Best Fit – This should be the most obvious feature of MasterPlex QT v4.0. With a click of that magical Best Fit button , the curve-fit is automatically optimized for you!
Best Fit Parameters – With the latest release of MasterPlex QT v4.0 (6/1/2009), the Best Fit can be optimized on 3 different parameters:
1. Root mean square error (RMSE) – This is the default and recommended option.
2. R-Square – This was the previous default parameter for the Best Fit feature.
3. Standard Deviation of % Recovery – This is a feature that was requested by our end-users and we came through for them.
This feature can be accessed via the Plate preferences icon in the Plate tab.
Quick Grouping of Replicates – Are you finding yourself manually grouping all your unknown replicates? This will be a huge time-saver for you. After grouping your first unknown replicate group, you should see a small black square appear in the bottom right-hand corner.

Click and drag this square across the rest of where your unknown groups are located and see what happens =)
Virtual Plate – Do you need to stitch or merge multiple files together? Or how about using your standard wells from one file to use on a different file? The Virtual Plate is your answer!
WYSIWYG Data Table – The flexibility of the pivot-style Data Table should not be underestimated. You have the power to sort, filter, add and remove columns easily. To sort, simply click on each of the column headers. The first click will do an ascending sort and the second click will do a descending sort . Certain columns will allowing filtering. To see if a column allows filtering, hover over with your mouse and you should see a pin appear in the upper-right hand corner. Click on the pin and you will see a list of values that you can filter for. A good example of this would be the Group Name column. To add other columns, click on the Show Columns Selector button. Then click the header you want to add and drag it onto the header row of the Data Table. To remove, a column header, simply click on it and drag it downward until you see an X appear. Then release the mouse button and the column will be removed.
Templates – Did you spend hours on creating the perfect Data Table layout? Save time on the next analysis by saving this layout to a template by clicking on the Table Template button and press Save. When you are ready to use it next time, just press Load and your data will appear as if you spent hours preparing it! The plate layout under the Plate tab also has a template system where you can save your well grouping information and standard information. Click on the Template Manager icon and the same procedure applies here as with the Data Table templating system.
Plot Unknown Data Points on the Standard Curve – Check the Plot unknown wells checkbox under the Standard Curve tab and you will be able to see where your unknown data points fall on the standard curve.
Automatically Detect Outliers – The Automatic Outlier Detection system will save you time from analyzing data that is not statistically significant or should not even belong in your data set. Choose your thresholds based on MFI, Concentration, Count and/or Standard Deviation. Click the Plate preferences icon and select the Plate tab to begin picking out those bad apples.
Chart Customization – Do you find the default chart colors or styles repulsive? Then change them by clicking the Chart properties icon and give it a makeover. You can edit everything from the legend to point labels.
Custom Reports – The Data Table is extremely flexible but it may not be the perfect solution for you. In this case, the Custom Reporting feature is the answer. Browse through our publicly available of report templates and download the ones you like. Then go to the Export Manager tab in MasterPlex QT v4.0 and select Import. Browse to the file and press Open. Then click Apply and the report will be automatically generated and saved for you. If the file has an .xml extension, try opening it up in Excel to see the final product. If you would like a custom report template to be made for you, please feel to contact us regarding the details.