[Histonet] Re: Water appropriate for IHC

[Brian Chelack]

A good rule of thumb for our lab is to use pyrogen free
water for any application where enzyme activity is critical.
We have a good ultrapure water system in our glassware and
media prep lab, but every once in a while we had
unexplainable declines in staining intensity. The only
explanation that we could come up with was that these
systems do not remove all pyrogens from the water(these can
be small < 10,000 mw non-charged molecules that can inhibit
HRPO or Alk phos reactions. These molecules can vary
seasonally in the feedstock water, and their concentration
in your lab water will also be dependent on how well the
water purification system is maintained.  Since we have
changed over to using pyrogen free water (used for surgical
irrigation), we have had fewer of these types of unexplained
staining isses (not to say that we don't have other staining
issues though...) This type of water is not cheap, but
neither are stain repeats.

Brian Chelack
Prairie Diagnostic Services