Basic Tissue Orientation and Paraffin Embedding Technique

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Author: Joelle Weaver MAOM, HTL(ASCP), QIHC
Reviewer: Rosemarie Tavares Proulx, BA, CT(ASCP), HT(ASCP)CM; Karen Stiffler, MA, HTL (ASCP)

This course will discuss the fundamental methodology, purpose, and skills needed for basic to intermediate level proficiency in routine paraffin embedding of human tissue samples. Paraffin embedding is the standard technique used in nearly all clinical and most research histopathology laboratories to produce human tissue blocks for microtomy. The production of properly oriented, accurately labeled, and contamination-free blocks is an essential skill needed by the bench histologist. Some of the background knowledge needed for the embedding task includes: an understanding of tissue sampling, human anatomy, tissue identification skills, and attention to fine detail, accuracy, and manual dexterity.

Continuing Education Credits

Objectives

  • Apply human tissue sampling and anatomy concepts to identifying human tissue types commonly encountered in histopathology.
  • State the primary steps of paraffin embedding and the purpose of each step in the technical process.
  • Describe and list the tools and instrumentation needed for paraffin embedding.
  • Identify selection criteria, such as optimal temperature ranges, for the desired technical performance from a selected paraffin embedding media.
  • State guidelines and identify the correct 3-D orientation for human tissue specimens commonly encountered in histopathology.
  • Identify quality control (QC) measures which help prevent cross-contamination and which promote high quality tissue sections during subsequent microtomy.

Course Outline

  • Background Knowledge
      • Introduction
      • Basic Anatomy and Tissue Identification
      • Spatial Reasoning and Visualization
      • Commonly Used Anatomic Direction Terms
      • Use of Tissue Marking Inks/Dyes with Basic Tissue Sampling
      • The terms "superior" and "inferior" are used to indicate a position or relationship and can be translated to mean the same as:
      • Tissue marking ink/dyes must be clearly visible both macroscopically and microscopically.
  • Tools and Instrumentation
      • Tools and Instrumentation
      • Base Molds
      • Forceps and Other Tools
      • Which of the following is NOT a tool or instrument utilized for routine paraffin embedding?
      • Cool forceps are recommended for use during paraffin embedding.
  • Purpose and Methodology
      • Purposes of the Embedding Task
      • The Essential Steps in Routine Paraffin Embedding
      • Step One: Open Cassette
      • Step Two: Examine and Identify the Specimen
      • Step Three: Orient and Position Specimen According to Tissue Type
      • Final Steps: Four Through Seven
      • Review of the Basic Steps for Routine Paraffin Embedding
      • Which of the following is NOT a purpose of the embedding process in routine histology?
      • Place the basic steps for paraffin embedding in the order that they are performed.
  • Paraffin Media
      • Modern Paraffin Media
      • Know Your Paraffin
      • Paraffin Temperatures
      • Paraffin with a melting point of 55° C has been selected for embedding. When regulating the holding reservoirs in the embedding center, at what a...
  • Basic Tissue Orientation
      • Basic Tissue Orientation
      • Uncomplicated Specimens
      • Small to Medium Sized Specimens with Multiple Pieces
      • Regularly Shaped, Medium Sized Pieces
      • Specimens Containing a Lumen
      • Appendix
      • Placenta
      • Cysts and Other Hollow Structures of Larger Circumference
      • Gynecological (GYN) Specimens
      • Endoscopic Biopsies
      • Skin Specimens
      • Elliptical Skin Specimens
      • Punch (Trephine) Biopsies
      • Shave Biopsies
      • Needle Biopsies
      • Breast Cores
      • Review: General Orientation Guidelines
      • A small tubular artery is received in histology to rule out temporal arteritis. When embedding this specimen, how must the sections of the tube be ori...
      • On all of the following specimens, the histologist is given the embedding orientation instructions to "embed on edge." For which specimen is this orie...
      • Fallopian tubes, vas deferens, and blood vessels should be embedded on their SIDES.
      • Without any other clear orientation triggers, tissues with a cut surface will be oriented so that the cut surface is placed down in the mold.
      • Identify the tissue type shown in the cut surface of this paraffin tissue block.
  • Troubleshooting and Quality Control
      • Basic Quality Control
      • Preventing Cross-Contamination
      • Sub-optimal Specimens
      • Practices for Specimen Loss
      • Communication
      • A common source of cross-contamination or carryover of specimen fragments to other specimens is the failure to wipe forceps completely clean between s...
      • A final microscope slide shows a tissue section with an incomplete outline that is not representative of the submitted specimen. What is one of the MO...
  • References
      • References

Additional Information

Level of instruction: Beginning to intermediate
Intended audience: This course is intended for histology bench technicians and technologists, new staff, and students.
Author information: Joelle Weaver MAOM, HTL(ASCP), QIHC is a certified histotechnologist with experience in clinical, research, and reference histopathology. She has received qualification from the ASCP in Immunohistochemistry and is a local ASCP representative for the Nashville, Tennessee area. Joelle's bachelor's degree was received from Bowling Green State University and her master's degree was awarded from Bluffton University. Positions held include education coordinator, lead instructor, and program director of a NAACLS accredited HT certification training program.
Reviewer information: Rosemarie Tavares Proulx, BA, CT(ASCP), HT(ASCP)CM has over 20 years of experience as a laboratorian, anatomic pathology supervisor, and laboratory manager. She is the former Anatomic Pathology Laboratory Manager at Boston Children's Hospital She is currently the Educational Coordinator for the Histotechnician Program at the Community College of Rhode Island.
Reviewer information: Karen Stiffler, MA, HTL (ASCP) has over 15 years of experience combined as a histotechnologist and a Program Director for Histotechnology at Lakeland Community College. She is currently a Professor and the Program Director for Histotechnology at Lakeland Community College. She holds a bachelor’s degree in Biology from Case Western Reserve University and a Masters of Arts in Teaching from Western Governor’s University.
Course description: This course will discuss the fundamental methodology, purpose, and skills needed for basic to intermediate level proficiency in routine paraffin embedding of human tissue samples. Paraffin embedding is the standard technique used in nearly all clinical and most research histopathology laboratories to produce human tissue blocks for microtomy. The production of properly oriented, accurately labeled, and contamination-free blocks is an essential skill needed by the bench histologist. Some of the background knowledge needed for the embedding task includes: an understanding of tissue sampling, human anatomy, tissue identification skills, and attention to fine detail, accuracy, and manual dexterity.
This course is part of:
Diagram of the layer of the skin.
A histologist performing routine paraffin embedding.
A punch skin biopsy specimen.
Specimen with requisition
Specimens 400x
Add additional molten paraffin after replacing the cassette bottom on top of the positioned specimen and base mold.
liver biopsy
Choose appropriate mold size for specimen type leaving enough space around specimen for a paraffin border.