Tag Archives: quality analysis

Quality Analysis and Quality Control of IHC Stains

At Caris Lifesciences, all of the stained slides went through a quality control process before they were able to leave the laboratory. Once out of the lab, they were looked at by a pathologist who put together a recommended treatment plan for rare and hard to treat cancers. They used a combination of immunohistochemical (IHC) stained slides, a molecular profile, and a comprehensive database of patient treatment. All of this was done in house, which helped Caris shine from the rest of the theragnostic labs.

As I progressed as a histotech, I learned more and more about looking at slides and stains to determine if things stained properly. I received training from pathologists, coworkers, and supervisors. If I had a question on a stain, I would always get the best answer I could from a supervisor. It was  painstaking to learn it all, but it really helped me develop and understand and knowledge base of the stains we performed and also what a lot of tissue looks like under a microscope.

quality control and analysis using H&E
This is a hematoxylin and eosin, or H&E stained slide. These are the bread and butter of histology. Most diagnostics start here. This is a section of colon.

The majority of what I learned was developed when I was making tissue micro-arrays (TMA). Please see the section I’ve devoted to TMAs.

quality control and analysis TMA
This is a very large tissue micro-array

Quality control for the automated stainers (Ventana and Dako) consisted of looking at the TMA section placed on each slide. These act as positive controls for the stains. Several different tissue types were present that were know to stain positive for all of the stains. I was in charge of selecting tissue and passing the tissue by sectioning and staining each tissue type for all of the stains it was supposed to stain positive for. This was step one of the quality control process.

quality control and analysis HER2
This is a HER2 positive stain on breast tissue. It’s one of the prettiest stains resembling a stained glass window.

The final step before the slides were delivered to a pathologist was the QC stage. Someone would sit and look at the TMAs on each slide and also the tissue to make sure that it didn’t fall off and had a uniform stain. Sometimes in microtomy a section can be placed on a slide that is thick on one side and thin on the other, or had chatter or other anomalies. Once this was done, the case was logged and sent out of the lab. I spent a lot of days at the QC station. It was always a nice change of pace from the frustrating microtomy or monotonous staining procedures. It was fascinating to see all the different types of tumors and stains.

Microscope: Compound and Dissecting

I’ve spent a lot of time in front of a microscope either chasing around a micro invertebrate to analyzing a histological stain for Q/A. During lab courses in school I was always the one person that was good at following around single celled organisms so everyone could get a glimpse at it.

When working at the Desert Studies Center, Zzyzx, CA on the Mohave Tui Chub project, I spent huge amounts of time in front of a stereo dissecting microscope counting zooplankton. It was very tedious work, but a really fun way to explore a world invisible to the naked eye.

microscope
This is the setup I used for counting zooplankton through a stereo dissecting scope

At Caris Lifesciences, working in the immunohistochemistry (IHC) lab required immense amounts of microscopy work. We had really nice stereo compound microscopes that every single slide went through. When I was making tissue micro-arrays (TMA) I had to quality control (QC) all kinds of tissue to make sure they would work for use in the TMA.  I also spent a lot of time looking at each of our IHC stains to make sure they stained properly and the stainer machines were still staining with the intensity we were looking for. In order for a slide to leave the lab and get in front of a pathologist, it had to go through our internal quality analysis (Q/A) team.