[Histonet] RE: Tissue Processing Protocol for Small biopsies part 2

[Ian R Bernard]

Regarding the fixation time for breast biopsies, after doing some more research, I stand corrected (not 72 but up to 18hrs.) with the maximum amount of time for fixation in order  to preserve the ER antigen in immunohistochemistry.

See this paragraph taken from CAP website:

"The type of fixative also has an impact on the results of estrogen receptor determination. Most labs use 10 percent buffered formalin. It's a great general fixative. It doesn't make the tissue too hard, and it fixes tissue reasonably quickly. Optimum fixation time for estrogen receptor activity is between six and 18 hours for buffered formalin. Less than that and more than that, you're going to get a diminution in estrogen receptor or even a false-negative. The optimum fixation time also includes processor time. Consider your tissue is sitting in a processor over the weekend in 10 percent buffered formalin for up to 48 hours. You may well end up with false-negative reactivity or at least lowered estrogen receptor reactivity in breast cancer. Too little fixation is also a problem. It is a problem that I encountered in testing for estrogen receptor on breast cores. Our breast cores on the biopsy processor were getting a total of eight to 10 hours of fixation. The laboratory changed its procedure and started processing immediately after loading biopsy tissue. All of a sudden my breast cores were getting only two to six hours of fixation. And there was a falloff in estrogen receptor activity."

Though I'd double check myself.

Ian R. Bernard
Ian R. Bernard, MSHA, HT (ASCP)
10th Medical Group- Anatomic Pathology Lab
USAF Academy, CO 80840

From: Ian R Bernard
Sent: Sunday, May 13, 2012 11:15 AM
To: 'histonet <@t> lists.utsouthwestern.edu'
Cc: BERNARD, IAN R MSgt USAF USAFA 10 MDSS/SGSH
Subject: Tissue Processing Protocol for Small iopsies

Fellow histonetters, I'm looking for evidence based or best practice/ benchmarked tissue processing protocols for the small biopsies listed below.  Please provide a reference since our facility strives for evidence based  procedures for our patients .

I am processing a number of:

-          Endoscopic or gastroenterology biopsies

-          Breast Core Biopsies


Currently, owing to one processor (Sakura, Tissue Tek- VIP-5), we put all tissues on our 12 hour processing run.  As a result, the endoscopic tissue, owing to its size, tends to be more dehydrated. To avoid the chatter artifacts associated with over dehydration, we soak these specimen blocks, a minimum of 15 minutes before sectioning with minimal or no chatter. We are hoping to improving turnaround time( to the pathologist) by  not having to soak so long. Thus, we feel that a tissue processing  protocol of less time will make a difference.

As we all know CAP and ASCO, have recommended breast core biopsies (the evidence based standard for determining breast cancer) be fixed at a minimum of 6 to 72 hrs before processing to accommodate accurate testing of immune stains ER. PR and Her2Neu for breast cancer determination.

Our processor reagents are as follows: 10% Neutral Buffered Formalin x 2 changes; 70% isopropanol x 1; 95% isopropanol x 1; 100% isopropanol- x 3 changes; clearing reagent- x 3 changes; and paraffin- 4 changes.  By the way, we are looking at purchasing another processor- my next communicated topic to accommodate processing of our small biopsies.

Question: is it ok to mix endoscopic with other small tissues such as: cervical bxs, shaves, ECC or EMB specimens on the same endoscopic processing protocol?  Again provide a reference as a matter of evidence based medicine. We do this to  try and split cases to avoid cross contamination at the grossing, embedding and cutting.  We consider this a QA mechanism for maintaining the integrity of the specimen cases.



V/r
Ian R. Bernard
Ian R. Bernard, MSgt, USAF, MSHA, HT (ASCP)
10th Medical Group- Anatomic Pathology Lab
USAF Academy, CO 80840