Ever needed to perform a reinjection after a run on CE platform ? You are not alone! We get questions all the time about how to perform reinjections on the 3500 Genetic Analyzer. So let’s go through it step by step.
The first thing you should know about performing a reinjection on the 3500 is that it can only be initiated after a run has started and while it’s in progress. Otherwise, before your run has started or if your run has already completed, your option is to Duplicate an existing injection. A reinjection, , allows the user to either keep the original injection and run conditions or change how the sample is injected by altering the instrument protocol .
So, let’s start a run!
There are several ways to reinject your samples.
Let’s start by viewing the Monitor Run Screen. Now that our run has started, you will be able to select any sample that you wish to reinject by selecting the well from the Plate View. Once you highlight the sample, navigate to the top toolbar and select the Reinject button; a pop up box will appear. This is where you can choose to reuse the existing protocol for that sample, modify the existing protocol, create a new protocol from a template, or use a protocol that exists in your library. You also specify whether you want the reinjections to occur immediately after the original sample injection or after all the injections that are still pending. Finally, you will be asked if you would like to reinject an allelic ladder with your sample, eliminating this extra step on the front end.
Remember that when you specify individual wells for reinjection, the instrument must still physically inject all 8 or 24 capillaries for that capillary array. However, the data is collected for only the wells that were selected for reinjection. If you wish to reinject more than one sample, hold down the control key and select each desired sample. This step is essential for consolidating the number of injections it takes for your instrument to perform the required reinjections selected.
So how do I know that my samples are being reinjected?
In the Plate View, here’s how you see it. The reinjection number is displayed for all samples in the re-injection, not just the samples selected for data collection.
But wait…there are other ways to reinject! You can also perform reinjections from the Instrument Run Views and Flags Screen. On the Array Tab, select the corresponding capillary number, for an 8 cap or 24 cap array. Alternatively, the flag table displays a quick preview of sample quality and identifies samples that may need investigation. If you would like to reinject samples that have been flagged, you can select the samples directly from this table. Remember to hold control and click if you would like to make multiple selections prior to hitting Reinject.
The final location to perform a reinjection is in the View Fragment/HID results screen. In this screen, the samples have gone through a primary analysis, giving you electropherogram data and flags to review and assess overall injection quality. . To reinject from this screen, simply highlight the necessary sample or samples and click the reinject button located in the top toolbar.
That’s it for now. Hope this was helpful.
If you have any questions or would like to see more such videos, submit your questions at thermofisher.com/forensicfocus
And don’t forget- when in doubt, you can always refer Back to Bases!