Do I still need to add UDIs to my libraries when using UMIs ?

Yes, the UMIs are random 6 nt sequences that will be added to all samples. Therefore, the UMI sequence cannot be used to uniquely identify the different samples – only to tag distinct random priming events during library generation.

Learn more about UMIs, their function, and usage in our Lexicon Chapter #8.

The 12 nt Unique Dual Indexes (UDIs) are still required if multiple libraries need to be uniquely barcoded and pooled for sequencing in a single lane or run. The UDI sequences are added during the endpoint PCR and read-out during sequencing with index reads 1 and 2, respectively. The index reads are required for sample demultiplexing after sequencing.

The UDIs required for the final amplification of QuantSeq libraries are included as a bundle in every QuantSeq Library Prep Kit (Cat. No.s 191 - 196).