RE: [Histonet] 37% formaldehyde & the UK & Europe

From:"Morken, Tim - Labvision"

Ah...the annual formaldehyde / formalin discussion, destined to recur ad

>From my reading this is what I have been able to deduce: 
Technically, formaldehyde is the gas only (paraformaldehyde being the
polymerized form). ANY solution of formaldehyde in water is technically
termed "formalin". 
This gas in water is a saturated solution at 37% (by weight) or 40% (by
Any dilution, then, is a percentage of the saturated mix. 
So 10% formalin is roughly 4% formaldehyde in water. 
Unfortunately, manufacturers ( for example, Fisher) have decided to call the
saturated solution "formaldehyde" thereby forever confusing the issue.
So we have to use terms like "10% formalin  (4% formaldehyde)"  or
"concentrated formaldehyde (37%)" to clarify every time we write a

Here are the Fisher Scientifc products in my catalog.  

Formaldehyde, 37% by weight
Formaldehyde, 40% by volume
Formaldehyde, 10% w/w
Formalin, neutral buffered, 10%
Formalin, 10% solution

Note that Fisher uses "Formaldehyde" for the saturated solution as well as a
solution of 10% by weight (that's 10% formaldehyde in water), and "Formalin"
for the dilution of the saturated solution (4% formaldehyde).

Sigma calls it "Formaldehyde Solution (Formalin) 37% in water."

It doesn't seem to me that anything will change, and for clarity, we'll all
have to keep indicating the actual percentage of formaldehyde our soluions

Tim Morken

-----Original Message-----
[] On Behalf Of LEWIS, MARK
Sent: Friday, February 04, 2005 12:53 AM
To: Linda Blazek;;;
Subject: RE: [Histonet] 37% formaldehyde & the UK & Europe

Concerning Formaldehyde & Formalin.. I would like to hear from our
colleagues from around the world concerning the terminology and meaning of
the differences between Formaldehyde and Formalin. I was always under the
assumption that Formaldehyde was a gas "put" into water at it's highest
concentration of 37 - 40 %. This 37-40% Formaldehyde when it is diluted with
water then becomes or receives the terminology called Formalin whether it is
10 %, 20% etc... I am over in the UK and have been having some controversy
with my colleagues here in that they want to use "concentrated formalin" for
a particular procedure. If I take the formaldehyde purchased from my vendor
and make up what I call a concentrated solution ( 37% solution), I will have
37% formalin, not the same thing. I feel that is confusing especially for
those of us across the ocean, because I will want to ask How concentrated?
If I hear the word formaldehyde, then I think of the 37-40% that we use to
make up our 10% NBF and I associate that in my mind as concentrate.  I
especially would like to hear from those in other countries across the
world. I even looked at a bottle of Formaldehyde that they have and it says
Formaldehyde (formalin). I'm going to search some texts and talk to some
chemists just because I want to be saying the correct thing without
confusing everyone when it comes to the procedure being done. Thanks !
Mark Lewis

	-----Original Message----- 
	From: on behalf of Linda
	Sent: Thu 2/3/2005 3:07 PM 
	Subject: RE: [Histonet] 37% formaldehyde

	It's probably a good thing I wasn't here to deal with it last night.
	Sometimes my mouth can get me in trouble.  I would have loved to
	him the gas.
	>>> "Stapf, Ross"  02/03/2005 3:04:45 PM >>>
	So he wanted a pure formaldehyde gas?
	I wish you had some around to give him.  :)
	Ah the confusion between formaldehyde, formalin, and 10% NBF.
	It can make for some great "Who's on first" type moments.
	Ross M Stapf
	Histopathology Manager
	Baylor University Medical Center
	3500 Gaston Ave.
	Dallas, TX 75246
	214-820-4110 fax
	-----Original Message-----
	[] On Behalf Of
	Sent: Thursday, February 03, 2005 1:53 PM
	Subject: RE: [Histonet] 37% formaldehyde
	There isn't any mistake about what he wanted.  One of our techs was
	late last night because one of our more "cranky" surgeons was doing
	procedure in OR.  He called to the lab for "formaldehyde".  He was
	formalin.  He preceded to yell (very loudly) that he did not want
	formalin he wanted "formaldehyde".
	>>> "Connolly, Brett M"  2/3/2005 2:40:22
	I think Geoff hit the nail on the head. The surgeon doesn't realize
	remember that 'formalin' is supposed to be 3.7%. I feel bad for the
	-----Original Message-----
	[] On Behalf Of
	Sent: Thursday, February 03, 2005 1:48 PM
	Subject: [Histonet] 37% formaldehyde
	Does anyone know why a surgeon would want to send a liver biopsy
	specimen in 37% formaldehyde?  Is there some test or procedure that
	would ever want to put a specimen in 37%? Thanks
	Linda  Blazek, HT (ASCP)
	Department of Pathology
	Children's Medical Center
	Dayton, Ohio  45404
	(937) 641-3358
	fax (937)641-5482
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