TISSUFIX, what improvement does it bring?

For a while now, histology laboratories have standardized tissue fixation using 10% neutral buffered formaldehyde. Proper fixation is essential because all the following laboratory procedures rely on adequate fixation to render quality results possible.

In an ideal world, under optimal conditions, most tissues would be well fixed with this solution. However, the world we live in is not always being optimal. Here are a few challenges that laboratories encounter and that can hamper the fixation results.

Tissue cut too thick as pathologists an PA tend to want more than less tissue, while the recommended fixation protocols are for 3 mm thick tissue

Tissue samples arriving late in the day at the laboratory without exact knowledge of when it was immersed in formalin, if it was at all. Since tissue processors usually run overnight, one could be tempted to put this tissue in the run about to start relying on post fixation that’s happening in the processor. This is unfortunately often not enough.

Tissue coming from OR that was left on the bench until someone came out and was able to place the tissue I formalin. Usually the formaldehyde containers are not opened in the OR because of the formaldehyde vapors emitted that could be detrimental to the patient and staff alike. During this waiting period, enzymes start their work and the necrosis process gets underway. Unless the tissue if fixed very rapidly, this process could lead to important structures or proteins being damaged past the point of being adequate to provide the information required by the pathologist to diagnose the tissue.

Tissue being excised in a remote location in the colder months and shipped to the laboratory may be exposed to temperatures low enough that the formalin, which is made of 90%+ water, may freeze and the tissue may not be fixed at all and completely lost

TISSUFIX is a neutral buffered formaldehyde solution whose formula has been optimized to provide faster fixation. Evaluations performed comparing it to NBF have demonstrated that if fixes 30 to 35% faster than normal formalin. By using the same basic ingredients, it provides similar fixation results, just happening quicker.

In the examples below, faster fixation will provide more complete and adequate fixation of thick pieces of tissue. It will be more forgiving for tissue not exposed to the fixative a long time because it the same period it will have penetrated deeper, enabling a possible acceptable fixation result even for shorter periods that the recommended 18-24 hours. As soon as a tissue left on the bench is immersed, the more rapid penetration of TissuFix will help diminishing or preventing necrosis altogether. And TissuFix is more resistant to freezing than NBF offering a better chance of receiving adequately fixed tissue from remote locations in the winter time.

Multiple laboratories have experimented with TissuFix over the past 30 years and are sold on its advantages. Implementing its use will help in providing better results to the pathologist for enhanced diagnostic information for the clinician.