Decalcification: Not So Hard

Decalcifying bone is an expensive process. Dollars are usually wrapped in tech time. Here are some proven pointers that do work and can shave off up to 1/2 the time from that old static “put-it-on-the-shelf-and hope-for-the-best” method.

The following ideas were proven in a well established “bone” lab in Washington State. Hopefully, these suggestions may help contribute to quicker decals in your neck of the woods:
1. Fix, Fix, Fix. You just gotta do it. NBF is generally good. Yes, alcohols may work though can disrupt morphology; do keep the concentrations down to about 60-70%. Be very aware what will happen when using nitric or sulphuric acids. Call the immuno companies what they recommend for decal when doing IHC on bone when conducting their IHC method. IHC results can greatly be affected with Formic acid solutions depending on time, density, etc.  Check new innovations and keep your pathologist very aware of distinct variations.  Naturally, larger specimens take longer, so trim specimens to what is needed.
2. Trim as much soft tissue from bone as possible. This improves fixation by a mile no matter what you use.
3. Trim bone to the area of interest. Why decal more than necessary? However, you may  trim a little more just in case you want to demonstrate a margin of normal stuff.
4. Suspend bone in a gauze wrap. Let as much decal chemical flow easily and all around that specimen; more heavy Ca+ really do drop to the bottom when a little motion is used. Placing bone in cassettes is fine providing you use those with the big holes; otherwise, very little flow occurs, even on rotator plates.
5. Securely place specimen preps in a sealed container on a rotator plate. Keep that solution moving in and out of the wrap or cassette. Have you seen solution not moving do a better job? Why do texts say to agitate during staining and processing? Gotta keep the fresh solution available all the times.
6. Decal solutions are usually 5-10% Formic acid and tha is routinely sufficient. Higher concentration doesn’t mean quicker without sacrificing cell quality. Using RDO agents are ok but you really need to be on top of the process hourly-no kidding.
7. End-test methods do differ considerably. X-ray is a definitive end-point pleaser. If you don’t have a small  x-ray unit in the lab, check with radiology for assistance if possible. Shared resources are a plus with directors saving money. Point to ponder when using x-ray end-points: you have a daily record in pics that your decal process is working well. They are superior records for the FDA/CAP inspectors and clients. This can also validate your end-point decal is complete with certainty. Nice job, people.
Chemical end point is good IF you can be sure you test method is foolproof. Are the chemicals made properly and consistently? Is the method consistently done? Check to see if your tech methods have splattered decal on the counter instead of in the test tubes… Still, chemical testing is not too bad.
Poking and cutting are not-so-good methods as it can destroy points of interest. Bending is…well…bending.
8. You can refresh your decal solutions twice a day which may help shave off about 1/2-1 day total time. Is it worth it, though? Mostly…yes. You add up routine waiting time to be sure.
9. Wash your specimens after decal and pay attention on final processing. Over processing, especially in alcohols/clearing agents can make even good decal stuff be on the brittle side no matter what you did above.
SO-what are you doing to speed up the decal process? Try to revise your current method with some (or all) of the pointers above. I know most of you are on budget crunches, but if you can “shave” off just one day on most specimens, then you have saved loads of money in a year. Your director might even thank you.
Well, that’s this tech’s opinion.

Keep us informed of your tricks/methods or if any of the above worked for you


Health of Pathology Laboratory Technicians at Risk from Common Solvents like Xylene and Toluene

Published: July 5 2011
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Rating: 4.4/5 (5 votes cast)

Study identifies increased incidence of Raynaud’s phenomenon among pathology laboratory staff who work with certain chemicals

Pathologists responsible for health and safety in histology and cytology laboratories will be interested in the results of a newly published study involving staff exposure to certain chemicals. Researchers determined that medical laboratory technicians who handle common solvents develop auto-immune connective tissue diseases in increased numbers.

The new study was published this month in the Journal of Rheumatology. It offers credible evidence that clinical laboratory technicians, pathologists, and scientists who work with toluene and xylene double their chances of developing a vascular condition known as Raynaud’s phenomenon (RP). And for those who work with toluene and xylene combined with acetone or chlorinated solvents, the chance of developing severe RP increases by a factor of nine!

Majority of Cases Involve Women Who Work in Pathology Laboratories

The study was conducted at the University of Otago, in Wellington, New Zealand. Researchers asked all the histology laboratories and cytology laboratories in New Zealand to participate in the study. Every laboratory department in the nation agreed and provided data and access to laboratory workers.

A total of 341 medical laboratory technicians participated in the study, most of whom were women (79%). Those who came into contact with toluene and xylene on a regular basis were twice as likely to develop Raynaud’s phenomenon. However, those who worked with acetone or chlorinated solvents combined with toluene and xylene were nine times more likely to develop severe Raynaud’s phenomenon.

Skin discoloration caused by Raynaud’s phenomenon, which can also lead to necrosis and gangrene. (Image sourced from

“I am concerned that 75% of those who worked with xylene or toluene handled wet sample slides without gloves. The majority had done so daily for over a decade,” said lead researcher Gordon Purdie, BSc, who is a biostatistician. “Absorption through the skin is a classic way for solvents to have a negative impact on health.”

As those working in histology or cytology labs know, these solvents are used during tissue processing to produce microscopic slides for viewing by pathologists. Researchers concluded that constant exposure to solvents is a contributing fact in the increased cases of Reynaud’s phenomenon among the study’s participants.

According to the study, medical laboratory workers who did not handle solvents developed severe Reynaud’s phenomenon at the same rate as people who did not work in medical laboratories at all. The researchers could therefore conclude that the increased incidence of Reynaud’s phenomenon cases among histology and cytology laboratory workers was the direct result of exposure to solvents.

Symptoms of Raynaud’s Phenomenon

Traditionally, Raynaud’s phenomenon results from exposure to cold or emotional stress that causes blood vessels in the hands, feet or other extremities to spasm. The alternating constricting and dilating of the vessels are called vasospastic attacks. They decrease the blood flow to those areas resulting in discoloration, and in extreme forms, can cause the skin to atrophy and lead to gangrene and necrosis.

This is the first study to demonstrate a link between medical laboratory worker solvent exposure and symptoms of auto-immune connective tissue disease, and has important implications for workplace health and safety,” said Andrew Harrison, Ph.D., a Senior Lecturer in Rheumatology at the University of Otago, and co-author of the study.

Study May Encourage Pathologists to Adopt Alternative Processing Methods

It is likely that this new study by the researchers at the University of Otago will motivate other researchers to also study the health impact of working with the solvents and chemicals commonly found in histology and cytology laboratories. The use of these chemicals for purposes of tissue processing and fixation is widespread. Thus, the findings of this study, if confirmed by future studies, will likely spur pathologists and histology laboratory managers to take steps to reduce staff exposure to these chemicals.

There are alternative methods for processing and fixing tissue that do not involve the chemicals that were the subject of the University of Otago study. One company that is a pioneer in developing automated tissue processing systems that don’t require formalin and similar chemicals is Milestone Medical. It offers an automated tissue processing system that allows the operator to choose “formalin or formalin-free fixation” and “xylene or xylene-free clearing.”

Milestone Medical may be among the first of the histopathology companies to recognize the demand by some histology laboratories for automated processing solutions that reduce the staff’s direct exposure to chemicals. But with this study, which links exposure to xylene and toluene to a higher incidence of Raynaud’s phenomenon, it is likely that more pathology laboratories will now want to look at how to reduce staff exposure to these chemicals—and possibly even eliminate their use.

Pathology groups and histology laboratories will probably also want to assess how this new research study might change the legal liability that the laboratory has, as it pertains to employees who have decades of exposure to xylene, toluene, and similar chemicals, and who may also show the symptoms of Raynaud’s phenomenon. In the United States, it doesn’t take long for attorneys to recognize a new legal cause of action and begin advertising to find individuals willing to be the plaintiff in a lawsuit.

Finally, it must be acknowledged that there is already a growing trend to re-design histology and cytology laboratories so that the odor from these chemicals is eliminated. In addition, enhanced use of automation and workflow redesign techniques reduces the direct exposure lab staff has to such chemicals. The findings from this new study linking use of xylene and toluene to Raynaud’s phenomenon may serve to accelerate this trend, for all the right reasons pertaining to staff safety.

Related Information:

Health Risk from Solvent Use by Lab Technicians (Press Release)


Questions and Answers about Raynaud’s Phenomenon

Comparison of Formalin-Free Tissue Fixatives: A Proteomic Study Testing Their Application for Routine Pathology and Research

Comparison of Formalin-Free Tissue Fixatives: A Proteomic Study Testing Their Application for Routine Pathology and Research (Archives of Pathology & Laboratory Medicine)

Health of Pathology Laboratory Technicians at Risk from Common Solvents like Xylene and Toluene, 4.4 out of 5 based on 5 ratings

3 Responses to “Health of Pathology Laboratory Technicians at Risk from Common Solvents like Xylene and Toluene”

  1. Ajit Alles says:

    This study looked at two organic solvents. The xylene/toluene free alternatives are also organic solvents- they have to be to remove paraffin or to permit transition from alcohol to paraffin. There is no evidence yet if these alternatives cause the same harm that the traditional solvents do. Be cautious about jumping on the bandwagon.

  2. Mutaz Ali says:

    I agree and this matches with our experience in Africa

  3. Linda Flynn says:

    I read this article with strong interest. I worked in very close proximity to a Histology area for over seven years and I developed Raynaud syndrome. It was quite bad. Since I am “out of the lab” and not exposed, my symptoms have abated and I only have a rare episode. I never made the connection.

    Thank you for this interesting article.



CPTC Medical Histology Technician Program… A Student’s Perspective

By: Nikkaiya Thompson 

The Medical Histology Technician Program at Clover Park Technical College (CPTC) is a four quarter length program. The last quarter is a clinical site experience.  The program is very concentrated because it is only a one year course.  I began this program fall 2010 and I am finishing my first quarter. The intense program requires hard work and dedication to completely finish. 

CPTC enters 20 students every fall quarter while most other histology programs throughout the U.S. are two years in length with fewer students.  Even though this program is relatively short, the instructor, Bekki Haggerty, has a high rate of students who have passed the national certification exam the first time.  Students have passed with a success rate of 93% compared to the rest of the nation, a fact which she is very proud.

Bekki is very passionate about histology having been in the field for over 20 years.   Her dedication to her students is 100%.  She is active in the histology community and expects the same from her students.  We are required to actively volunteer our time one way or another to histology.  She also encourages us to become members of the different histology societies to develop networking opportunities.  She reiterates the fact that histology is a very small career field.  Everyone knows each other and setting a good first impression will follow us wherever we go.

The start of the program begins with a mandatory meeting, Bekki stated that we will live, eat, and breathe histology for the entire year.  Histology will always be on our minds (and even in our dreams).  This is especially true when it comes time for an exam.  To reinforce this fact, she even has a sign above the entrance threshold saying “live, eat, breathe histology”.  During the very first week of the class we were given a thick packet of lectures. The information consisted of the safety standards of the lab, where you can work as a histology technician, and the histology workflow.  After the first week, we were given a final exam that everyone had to pass with a 76%, or above, in order to continue with the program. This sets the tone for the rest of each quarter.

Bekki’s grading policy is that you must have a 76% overall GPA at the end of each quarter in order to continue; anything below that is considered failing and you would be out of the program.  In addition, all final exams are comprehensive based.  For example, if you are preparing for your final exam for the third quarter, then you need to study all of the information for that current quarter PLUS all the information from the previous two quarters.  Bekki’s motive is to prepare each student for the ultimate HT or HTL national certification exam after graduating from the program. 

Bekki goes above and beyond scheduled class time by providing extra mentoring hours to ensure that we have an opportunity to hone our new histology skills.  She expects perfection from us so that we can be the best at what we do when we go out into industry.  She teaches us with very high standards, which is why she has the bragging rights about her students achieving such high certification pass rates.  Before exams, we always ask her if she expects us to know EVERYTHING. Her answer is always the same, “YES!”  I had come to realize that when I do study everything for a test, it may not necessarily be on the exam; however, it will probably be there on the certification exam.

Bekki is very astute when it comes to histology because the curriculum is well organized.   Each week is comprised of logical, sequential steps in histologic processes.  During the first quarter, we started off with fixation, which is traditionally the hardest block to get through because of the vast memorization required.  The subsequent topics are  grossing, processing, embedding, and microtomy. We learned each procedure, step by step, in the classroom and then applied that knowledge in the lab.  This teaching style facilitates the learning process and helps solidify the information and necessary skills needed to succeed.

Towards the end of the quarter we were given professionalism packets that discussed how to be professional in the medical field. It also contained scenario-based questions about how we would act and respond in certain situations.  One eye opening experience I had was when we watched a video about laboratory mistakes with patient specimens.  A patient received a wrong diagnosis and had to go through unnecessary surgery; a lab technician working with two open cassettes at the same time mistakenly swapped the tissue samples.  The video displayed the effect that histology technicians have on patient’s lives.  I learned that histology is vital to the medical community; we have to pay the utmost attention to detail and use caution while working with patient specimens.

Overall, the curriculum is quite demanding and our instructor, Bekki Haggerty makes clear the reason behind it.  If you are a dedicated, hardworking individual and are up to a challenge, then join the histology community!  It is hard work, but the rewards are all worth it in the end.

Articles are submitted to stimulate other opinions and do not necessarily represent the view of any particular histotechnology group or individual nor aspects of the WSHS. We wish to hear from anyone with opinion(s), comments, suggestions.  Any article submissions may be subjected to editorial examination before publication. Submissions may be emailed to Thank you for your cooperation.


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