[Histonet] Processing artifact - delayed start

[Bacon, Charles]

We have had 2 reasons why we saw processing issues like this:

1. I recently found out on our VIP 5 they did not turn the level sensors on during install. These sensors are known to error so often, Sakura tells technicians to set the default to off. All the processor can sense is pressure and time. So it may be that the formalin is not filling all the way. You are noticing this on delayed runs, but on those runs are you often stacking trays? If so, isolate the cases in the upper trays and review. 

2. We found a clogged line. This happens with the formalin lines if you don’t do the hot water flush often enough. This can be an even bigger issue if you recycle and re-buffer your formalin (we do not).

Good luck!

Chuck Bacon, HTL(ASCP)CM 
Supervisor Histology
Baystate Medical Center


-----Original Message-----
From: Verizon wireless <someperson43 at yahoo.com> 
Sent: Friday, February 2, 2024 10:37 PM
To: histonet at lists.utsouthwestern.edu
Subject: [Histonet] Processing artifact - delayed start

Dear Histonet Members,

We have terrible processing artifact if tissue sits in the formalin-filled retort (at ambient temperature) for too long (more than 10-12 hours) before a delayed process starts. The longer the wait, the worse it looks. We have Tissue Tek VIP 5 processors, and we process luminal gastrointestinal biopsies exclusively. I've attached some photomicrographs of problem cases on the Histonet Images website (with the same topic title). 
This artifact typically affects a few specimens per day (~2% or less), even though everything is done on the same processor; it may affect all tissue portions in a cassette or only some of the tissue in that cassette. Some tissue portions may only have the artifact on one half with the other half looking perfectly fine. The techs sometimes note the tissue feeling "crunchy" at the time of embedding and / or at the time of microtomy. These tissues tend to suffer greater chatter artifact and have trouble sticking to the slides. The sections look just as bad on recuts as the originals. Re-processing does not seem to help at all. 
If the cassettes sit in formalin in a container outside of the processor for days before the processor is loaded (with subsequent immediate start), things look perfectly fine. When we have staff around to start the processor immediately upon loading cassettes and empty immediately upon completion, the tissue looks perfectly fine. 

Our current processing program is as follows:

1. 10% Formalin, 30 minutes, ambient temp, p/v on 2. 10% Formalin, 30 minutes, ambient temp, p/v on 3. 65% Alcohol, 10 minutes, ambient temp, p/v on4. 80% Alcohol, 10 minutes, ambient temp, p/v on5. 95% Alcohol, 7 minutes, ambient temp, p/v on6. 95% Alcohol, 7 minutes, ambient temp, p/v on 7. 100% Alcohol, 10 minutes, ambient temp, p/v on 8. 100% Alcohol, 10 minutes, ambient temp, p/v on 9. Xylene, 15 minutes, ambient temp, p/v on 10. Xylene, 15 minutes, ambient temp, p/v on 11. Paraffin, 10 minutes, 60 degrees C, p/v on12. Paraffin, 10 minutes, 60 degrees C, p/v on13. Paraffin, 15 minutes, 60 degrees C, p/v on14. Paraffin, 15 minutes, 60 degrees C, p/v on

Obviously there are times we absolutely need to use delayed start. I would greatly appreciate guidance, and I'll be happy to provide any other details that might be useful.
Sincerely,
Brian Quigley MDLaboratory Director of a GI Pathology Laboratory