We have been seeing a very specific fail mode in about 1 in 10 runs since upgrading to v4 chemistry last year, and we wonder if anyone else is experiencing this or has thoughts to the cause.
When this happens:
Illumina suspects it's the "blue bubble" phenomenon that many users see since the upgrade, which is caused by the peltier being at a slightly higher temperature during the reaction (54 degrees instead of 52.5). But that should cause the "blue bubble" pattern on the intensity chart - higher intensity at the bottom of FC due to the cold reagent entering, and then lower intensity as it passes through. We're not seeing that here. Also, our engineer has made temperature adjustments to no avail.
Perhaps v4 chemistry is more sensitive and less robust than previous versions. Has anyone else experienced this?
Thanks!
When this happens:
- the Q30 starts dropping faster than normal, always at about cycle 50,
- only the center lanes are affected, 3-6 being most severe, 2 and 7 less so, and 1 and 8 never affected,
- always total recovery in the Index and Read 2, with normal Q30 for those reads
- accompanied by high pre-phasing.
Illumina suspects it's the "blue bubble" phenomenon that many users see since the upgrade, which is caused by the peltier being at a slightly higher temperature during the reaction (54 degrees instead of 52.5). But that should cause the "blue bubble" pattern on the intensity chart - higher intensity at the bottom of FC due to the cold reagent entering, and then lower intensity as it passes through. We're not seeing that here. Also, our engineer has made temperature adjustments to no avail.
Perhaps v4 chemistry is more sensitive and less robust than previous versions. Has anyone else experienced this?
Thanks!
Comment