I haven't done Illumina de-multiplxing before as the lab I am used to work with has done this by default. I'm now getting samples from a lab that says that it doesn't do de-multiplexing. It's a new lab which doesn't have experience with NGS so I am not quite sure they now what they are doing. So I got the following Illumina run (this is just a screenshot showing some of the files):

![screenshot of files][1]

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The SampleSheet in this folder has the following content (again a screenshot):

![samplesheet screenshot][2]

To me it looks like the data has been already de-multiplexed as the fastq files have the same names as the samples. What do you think? How can I test whether this is, indeed, the case? Also, I see some files (their names start with "Undetermined") which are not assigned to any sample. What shall I do with them?

 [1]: http://i.imgur.com/tBEef65.png
 [2]: http://i.imgur.com/O8HSVLP.png
<p>These are indeed demultiplexed. Providing demultiplexed files is such a simple thing for a sequencing facility to do that I&#39;m always amazed when one is too lazy to do so. The &quot;Undetermined&quot; files can be ignored. I never provide those to our users. I should note, though, that I routinely check how many reads are in that file, simply because if those files are large then there was an issue with the library or sequencing.</p>
