Since a few weeks we occasionally observe very big variation between raw cluster densities on our Single read flow cells.
Even if we load multiple lanes from the same library tube we sometimes see this. eg. variation was between 730K/mm2 and 164K/mm2 loaded from the same tube!!
Also aliquoted Phi-X for a dedicated control lanes sometimes has as little as 20k/mm2 clusters where it should be 500k/mm2.
aliquoting is something we do for years now with reproducible results up until a few weeks ago.
We only observe this with single read flow cells. We never see this with PE flow cells.
We used different sequencers, fluidics on cBot and sequencers are always checked and OK. Still we observe this, and can't get it under control.
Illumina is not aware of a SR flow cell issue, and also has no clue how to control this.
Has anybody seen this as well, or has anybody a clue what could be causing cluster density variation?
Even if we load multiple lanes from the same library tube we sometimes see this. eg. variation was between 730K/mm2 and 164K/mm2 loaded from the same tube!!
Also aliquoted Phi-X for a dedicated control lanes sometimes has as little as 20k/mm2 clusters where it should be 500k/mm2.
aliquoting is something we do for years now with reproducible results up until a few weeks ago.
We only observe this with single read flow cells. We never see this with PE flow cells.
We used different sequencers, fluidics on cBot and sequencers are always checked and OK. Still we observe this, and can't get it under control.
Illumina is not aware of a SR flow cell issue, and also has no clue how to control this.
Has anybody seen this as well, or has anybody a clue what could be causing cluster density variation?
Comment