Histonet Digest, Vol 140, Issue 5 specimens lost
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Steve McClain
2015-07-07 18:06:42 UTC
Raw Message
The problems associated with tissues lost are quite similar to those with floaters.
Here is a newly edited copy of what I posted a few years ago on floaters and you may find it useful.
We still wrap nearly all specimens. At times we cannot see minute flakes of tissue, but retrieve them by gently scraping the inside of the paper wrap.

Floaters on the water bath are generally not the problem, are usually identifiable, unlike the serious issue posed by floaters in the block.

In order to change the outcome, you (the institutional you) must change what you are doing.
SO start by first examining and then changing your grossing-procedure.

Start by scrupulously cleaning every pair of forceps.

Keep an open vial of 50% alcohol at the bench to have the grossers rinse their forceps between specimens.
Photograph every specimen-this forces the grossers to maintain a clean background. If you do not have grossing cameras, then mount a video camera above the grossing station and let it run. Point is a few hours study of technique can help identify where the problem is. Better than wasting many hours.

Have grossers begin to wrap every small specimen in lens paper- Four darn good reasons. Wrapping specimens with forceps helps to clean the forceps before the next specimen. At embedding , the action of opening/unwrapping specimens with forceps cleans forceps at the embedding center. Floaters can also occur during processing-wrapping specimens prevents floaters during processing and keeps processors clean.
(If you don't believe me- filter your first reagent next time you change it. Then process that to a block- I once inherited a processor from a lab that did placentas. We found pieces of placenta in our derm specimens as long as 5 or 6 months later.) Fourth, even if the specimen lid opens, the tissue is usually still inside the wrapper and is not lost. We bag and save our wrappers until the cases are signed out, but rarely have we had to go hunting.

Change fixative and clean block bucket at the grossing bench routinely.
You may wish to consider rinsing all blocks in fresh reagent BEFORE placing on processor.

As we evolved to this procedure, the floaters fell to 1 per 15,000, about 3 per year in our small lab.

Focusing on grossing is neither putting all your eggs in one basket nor blaming the grossers.

Focusing on grossing floaters is focusing on the complex, dirty workplace where historically the vast majority (70-80-90%) of these errors are generated.
The people may be part of the problem, yet the system is at the heart of the issue and the system determines the error-rate.

The system is complicated, but includes the environment and structure and policy.
There is too much going on at or near the grossing bench.
Make it quiet.
Make it simple.
Reduce distractions.
There are generally more grossers than embedders and greater variation in technique and sample size-(embedders generally only have to deal with samples 15x15mm or less.)
And greater numbers of reagents and fixatives And perhaps even a cryostat for FS Or FAXITRON.
Or a computer
Accessioning, scanning documents and cassette printing.
Maybe a telephone.
Or a reagent recycler
Or a processor
(eliminate as many distractions as you can. Separate quiet enclosed areas where specimens can be controlled and studied without distraction. For example we banned cellphones from the grossing area).
Point is simplify and reduce noise.
Make the grossing area for small specimens really quiet.
The singularly important reason we never adopted voice recognition in the grossing area had to do with the distractions imposed by messing with computers, the noise of talking into a machine, the distraction of looking at a screen to proofread while working with a one of a kind valuable specimen in the most error-prone area of the lab.
Talking and looking at words on a computer screen is neither studying tissue nor professional.
If you use that type of system, consider modifying your procedure to focus on getting the tissue cleanly in the block and the block safely in reagent, then do the dictation.
Some of our grossers were resistant to change with valid reasons for doing so we let them be the baseline control- when we wanted to make a change we compared method A to method B.
When one method was statistically better we showed them the data.
There is room for the inevitable disagreement- but study and get some data and restudy where needed.

Personally, I want to see grosser focused on the tissue, studying tissue as a trained professional; Once the tissue is safely in the cassette and in the next reagent (or fixative or ) then the grossers enter their own data.
Scan the next bottle barcode and move on to the next specimen.

'Clean' is a relative term and a perceptual problem.
(What is clean?-even when your grossing area is spotless-if one were to eat in the lab would you prefer to do so standing next to the grosser or the embedder? Not suggesting it is permitted- just which area is cleaner and what is meant by clean) SUGGESTIONS Have an EM (electron microscope) tech come in and get it clean to his/her satisfaction. They are used to clean-room mentality and standards.
Sometime Grossers are macho or otherwise reluctant to change paper towels or other cutting surfaces or cutting tools between specimens.
Make the tools and towels freely available.
Make the grossing benches spotless.
Make the reagent buckets, spotless.
Fresh reagents every shift- or whenever a speck appears.
The instruments, spotless.
Cut white or blue flat paper towels into 2.5x2.5 inch squares and gross on them- fewer floaters than brown C-fold towels or use pink dental wax sheets.
Make a hard and fast rule about the number of tissue fragments per cassette, e.g., 5- not more.
5 pieces in a cassette can be seen and verified easily.
Place similar sized pieces in cassettes (if there are 10 pieces, 5 each 1mm and 5 each 3mm- all the 1mm go into one cassette and all the 3 mm in the other cassette. A 1mm speck-floater is not obvious among 3mm pieces. A sixth 1mm speck in the 1mm cassette is noticeable.
Use a separate area to gross large specimens and small biopsies, whether on different benches or at different times of day than the small biopsies.
When one photographs every specimen as we do at McClain Labs and critiques grossers for knifemarks or bloody stains on the towel or leaving the same bloody background in consecutive photos by posting them in the lab or at staff meetings, they soon catch on. Rewards for great photographs also sends a message. Photography is a great method for verifying technique, for documenting your work, but it does slow us down. 11 years later, we still photograph every specimen.

METRICS- fewer is better.
Track floaters or lost specimens by grosser to see if you have an outlier or risk-taker.
Performance improves on any measured parameter when one follows through.
Historically grossing performance has been measured by how fast the grosser completes x number of specimens.
That metric should be suspended or abandoned if there are issues in the lab or while you are working toward improving technique.
FYI our lab has very few metrics.
Our main metrics are 1) lost specimens- (the number was zero in seven years and is now 1 in 11 years)
2) cumulative blocks since last maintenance for each processor.
3) catastrophic tissue loss- sounds a bit extreme, but is defined as any hole or missing tissue on the slide visible at low power (2x).
I photograph each such slide, investigate and generally find maintainance on the processors.
These we discuss at staff meeting of grossers and histotechs and pathologists.

Training histotechs to gross has a variety of benefits.
My good experience biases me -my best grossers have been histotechs.
They respect the difficulty in embedding and cutting and communicate well with other histotechs.
My second best are pathologists (I am the slowest)
Physician assistants and residents are difficult (or maybe I demand too much). Both operate largely outside traditional lab feedback loops. (Feedback to residents may amount to being castigated by the attending who is legally responsible for their mistakes at the microscope and feeling discomfort. But neither residents nor PA's have to embed or cut their mistakes at the microtome, which falls to the histotechs)
I'd rather gross myself than to clean up messes made by residents.
I was a jerk resident myself 1000 years ago- you know the trainee who is told to keep the blocks postage stamp-size and brings in a commemorative stamp?

The process for eliminating floaters or lost tissues is analogous to troubleshooting staining problems. Look to the early steps because errors in technique in the early steps cause great variation in the final product. Begin by eliminating early points of failure (for staining-first care in handling prior to fixation, followed by prompt fixation, adequate fixation, then consistent thickness in grossing, then processing, then cutting). Errors in early steps cannot be fixed later on. Mashing tissue or prolonged drying or inadequate fixation cannot be fixed by re-processing. Once the floater is in the block, it is there to stay and proof by testing the DNA of the floater and patient is expensive, used to be $3000-$5000.

It is better and less expensive to eliminate these errors at the source.
Focusing on grossing not only gets rid of the main source(s) of variation, it also serves notice to the embedders once "grossing floaters and "processing floaters" are eliminated embedding is next.

Steve A. McClain, MD
631 361 4000

631 361 4000

-----Original Message-----

1. Specimens lost during processing. (STEVEN PINHEIRO)