I was interested in Vinnie Della Speranza's query of last week about recycled formalin. His lab has a still on loan to try out for recycling formalin.

Why does a busy hospital histology laboratory want to recycle formalin? Is it to save money, or avoid disposal problems?

With the cost of ready-to-use formalin so cheap (Our contract price through a hospital consortium is about $15 per 5 gallons/20 litres), you cannot be saving much money when you count the cost of the still, electricity, assaying for concentration, buffering, checking the pH and time involved. Is it all cost effective? And are employees exposed to formaldehyde fumes?? Are there formaldehyde monitoring costs too?

Further, when you consider that patients are paying collectively hundreds of dollars to get their biopsies processed, it does not seem unreasonable to go first class and purchase ready-to-use formalin. The cost of chemicals to inactivate the formalin before disposal is relatively cheap too.

One of the benefits of passing time for hospital histology labs are commercially prepared reagents like formalin, Schiff's and special stains, and automated  stainers for H & E, special stains and IHC which give standardised and consistant results. Preparing your own formalin for fixation, using formaldehyde you have distilled,(and fixation is the most important first step in most histology procedures) is surely getting away from consistant results.

Then there is the effect of recycled formalin on IHC results, which Vinnie enquired about. My understanding is that if you use the HER2 protein expression test as the basis for a diagnosis, you must follow strict a FDA approved procedure, which includes formalin fixation. That fixation may also be affected by recycled formalin.I wonder how it affects other reactions?

Comments anyone? Am I missing something here?

(Curious) Mike Titford
Pathology Department
USA Medical Center
Mobile AL 36617 USA