Scott -

Two possible thoughts come to mind, especially with your clue of the
controls being purchased.

1. The controls may NOT be positive for whatever microorganism
you are staining (? helicobacter, spirochetes, Legionella ?)

The company may have cut through the positive area.

2. How long did the company store the slides after cutting them
before they sold it to you, and how long have you had the cut
slides before you used them?

Many microorganisms lose their staining ability if the cut slides
are stored for a long time. I've personally have seen this with
spirochete slides that are older than 3 - 6 months storage. At
3 months, I start seeing decreased staining, by 6 months I get
negative staining. 

Other people have reported to me seeing the same problem with 
Gram +/- and AFB. Bancroft's book reports this problem with amyloid. 
We see the same problem with some of our immuno controls (some as
soon as 2 weeks old). 

On all of these, if you go back to the same block, and cut new 
slides, the new slides stain wonderfully. Possible theory - oxidation 
of the tissue on the cut slides.

Some companies cut an entire block, stain every 6th section, and
store the unstained 5 slides plus the stained slide in a warehouse
somewhere, waiting for a lab to buy them. Some companies, knowing
that there is this problem, wait until the request comes in, the
cut the slides. The trick is to find out which company is doing
which technique.

Couple of suggestions - First, return all unstained slides back
to the company, and demand that THEY show that THEY can stain
these slides. Ask for your money back.

If you are cutting your own slides for bacteria, fungus, amyloid
and immuno, cut only enough slides to see you through 3-6 months
worth of special stains. When you stain the first and last slide
to check for positivity of the batch you just cut, date the slides
and file them with the cut slides. This can be part of your QC.
Throw away old slides that you know show decrease staining.

If you have to buy from a company, ask them (call, talk with them
at conventions) about if they cut sections upon request or if they
store the cut slides. Buy only from those who cut upon request.
(Not that this is the company's "fault". A lot of histotechs don't
know that long-term storage of cut control slides can cause
decreased or negative staining. It's a matter of educating 
everyone involved.)

If you have a positive case right now (your note said the patient's
slide turned out), then SAVE this block, and use this as your positive
control. Cut a few slides off of it now, and store these in your
control box. When you run out, or your 3-6 months is up, go back to 
the block and cut a few more slides. Or if you don't use this
control very often, cut a slide off the block when this stain
is requested. MUCH cheaper than buying controls.

If you do want to extend the life of cut control slides, some 
suggestions from other people include: dipping slides in melted
paraffin to get a coating on the tissue to stop the oxidation, 
store cut slides in refrigerator to slow down oxidation, store
slides in a cool place (not in cupboard that has an under the
cupboard light attached to it).

Hope this helps.

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

"Scott, Allison D" wrote:
> 
> We are having a problem with the steiner and steiner.  After the slides are
> put into the developer, the patient slides turn but the control slide does
> not.  We originally thought that the hydroquinone was not any good, so we
> got some new chemical.  The same thing happened again.We follow the
> procedure to the letter. IThe dry chemicals are not old.  Not that  it makes
> any difference.  We also have considered that the control slides may not be
> any good also.  On Monday we will repeat the stain using another control.
> By the way the controls are store bought. For those of you that responded to
> my problem of fungus growing among us, the problem is with the cytology
> area.  Were not sure where  in the cytology area but it is not with anything
> that histology did.  If anyone has a solution to my steiner problem please
> respond..
> Allison Scott