[Histonet] formic acid decal

Lee & Peggy Wenk lpwenk <@t> sbcglobal.net
Fri Jul 1 18:13:00 CDT 2005

A milder formic acid decalcification solution is FASC = formic acid-sodium
citrate. It's a buffered formic acid. Sections of vertebral bone take 5-7
days to decalcify. I don't know how long a bone biopsy takes. When my
students have to submit a bone section for their certification exam, this is
what we use. It gives great nuclear detail, fantastic eosinophil granules.
So I expect IHC would be equally great. We use the procedure out of the
Bancroft book.

65 mL of 20% aqueous trisodium citrate (13 g in 65 mL water)
35 mL of 90% formic acid (that's full strength. Don't dilute)
pH is about 2.3
Change solution every 3 days.

We did have a rare bone tumor, and none of the IHC worked, until we
decalcified it in EDTA. Then it worked great. (Sorry, don't remember what
type of tumor or what type of antibody.) But you might want to try the EDTA,
if you have a lot of time. Vertebral bone takes 2-3 weeks. The little bone
fragments we had from the bone tumor took 3 days. (would have been a 2-3
hours in our usual 5% hydrochloric acid)

25 g EDTA disodium salt (ethylenediaminetetracetic acid) (note: MUST be
disodium salt)
175 mL d. water
Solution is cloudy. Add 2.5-3.0 g of sodium hydroxide until solution becomes
clear. pH should be about 7 at that point.
Change solution about twice a week.

Peggy A. Wenk, HTL(ASCP)SLS
William Beaumont Hospital
Royal Oak, MI 48073

Lee & Peggy Wenk
-----Original Message-----
From: histonet-bounces <@t> lists.utsouthwestern.edu
[mailto:histonet-bounces <@t> lists.utsouthwestern.edu] On Behalf Of louise
Sent: Friday, July 01, 2005 8:32 AM
To: Histonet <@t> lists.utsouthwestern.edu
Subject: [Histonet] formic acid decal

Hi all,

on pain of being repetitive/lazy/slovenly/slothful/unprofessional,
would someone PLEASE share their recipe for formic acid decalcifying
solution suitable for samples on which IHc will be performed. Many many

Louise Renton (grovelling)
Bone Research Unit
University of the Witwatersrand
South Africa
"....I know who I am. No-one else knows who I am. If I was a giraffe, and
someone said I was a snake, I'd think no, actually I'm a giraffe"
Richard Gere

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